diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 22d47fec..6fb65532 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -462,6 +462,24 @@ parameters:
 			count: 1
 			path: src/Support/SelectFields.php
 
+		-
+			rawMessage: 'Method Rebing\GraphQL\Support\SelectFields::handleMorphToRelation() has parameter $field with no value type specified in iterable type array.'
+			identifier: missingType.iterableValue
+			count: 1
+			path: src/Support/SelectFields.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Support\SelectFields::handleMorphToRelation() has parameter $queryArgs with no value type specified in iterable type array.'
+			identifier: missingType.iterableValue
+			count: 1
+			path: src/Support/SelectFields.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Support\SelectFields::handleMorphToRelation() has parameter $with with no value type specified in iterable type array.'
+			identifier: missingType.iterableValue
+			count: 1
+			path: src/Support/SelectFields.php
+
 		-
 			rawMessage: 'Method Rebing\GraphQL\Support\SelectFields::handleRelation() has parameter $field with no value type specified in iterable type array.'
 			identifier: missingType.iterableValue
@@ -1032,6 +1050,36 @@ parameters:
 			count: 1
 			path: tests/Database/SelectFields/ValidateFieldTests/ValidateFieldsQuery.php
 
+		-
+			rawMessage: 'Method Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests\CommentsQuery::resolve() has parameter $args with no type specified.'
+			identifier: missingType.parameter
+			count: 1
+			path: tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests\CommentsQuery::resolve() has parameter $context with no type specified.'
+			identifier: missingType.parameter
+			count: 1
+			path: tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests\CommentsQuery::resolve() has parameter $root with no type specified.'
+			identifier: missingType.parameter
+			count: 1
+			path: tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests\CommentsQuery::resolve() return type has no value type specified in iterable type array.'
+			identifier: missingType.iterableValue
+			count: 1
+			path: tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
+
+		-
+			rawMessage: 'Method Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests\CommentsQuery::resolve() return type has no value type specified in iterable type array|Illuminate\Database\Eloquent\Collection.'
+			identifier: missingType.iterableValue
+			count: 1
+			path: tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
+
 		-
 			rawMessage: 'Method Rebing\GraphQL\Tests\Support\Objects\CustomExamplesQuery::resolve() has no return type specified.'
 			identifier: missingType.return
diff --git a/src/Support/SelectFields.php b/src/Support/SelectFields.php
index 661cb647..a4b20b06 100644
--- a/src/Support/SelectFields.php
+++ b/src/Support/SelectFields.php
@@ -193,7 +193,19 @@ protected static function handleFields(
                 }
                 // With
 
-                elseif (\is_array($field['fields']) && !empty($field['fields']) && $queryable) {
+                elseif (is_a($parentTypeUnwrapped, \GraphQL\Type\Definition\InterfaceType::class)) {
+                    static::handleInterfaceFields(
+                        $queryArgs,
+                        $field,
+                        $parentTypeUnwrapped,
+                        $select,
+                        $with,
+                        $ctx,
+                        $fieldObject,
+                        $key,
+                        $customQuery
+                    );
+                } elseif (\is_array($field['fields']) && !empty($field['fields']) && $queryable) {
                     if (isset($parentType->config['model'])) {
                         // Get the next parent type, so that 'with' queries could be made
                         // Both keys for the relation are required (e.g 'id' <-> 'user_id')
@@ -207,26 +219,29 @@ protected static function handleFields(
 
                         static::addAlwaysFields($fieldObject, $field, $parentTable, true);
 
-                        $with[$relationsKey] = static::getSelectableFieldsAndRelations(
-                            $queryArgs,
-                            $field,
-                            $newParentType,
-                            $customQuery,
-                            false,
-                            $ctx
-                        );
-                    } elseif (is_a($parentTypeUnwrapped, \GraphQL\Type\Definition\InterfaceType::class)) {
-                        static::handleInterfaceFields(
-                            $queryArgs,
-                            $field,
-                            $parentTypeUnwrapped,
-                            $select,
-                            $with,
-                            $ctx,
-                            $fieldObject,
-                            $key,
-                            $customQuery
-                        );
+                        // Check if this is a MorphTo relation
+                        if (is_a($relation, MorphTo::class)) {
+                            // For MorphTo relations, we need to handle them specially
+                            // because they can have different models, and we need to eager load based on the query
+                            static::handleMorphToRelation(
+                                $queryArgs,
+                                $field,
+                                $with,
+                                $ctx,
+                                $fieldObject,
+                                $key,
+                                $customQuery
+                            );
+                        } else {
+                            $with[$relationsKey] = static::getSelectableFieldsAndRelations(
+                                $queryArgs,
+                                $field,
+                                $newParentType,
+                                $customQuery,
+                                false,
+                                $ctx
+                            );
+                        }
                     } else {
                         static::handleFields($queryArgs, $field, $fieldObject->config['type'], $select, $with, $ctx);
                     }
@@ -265,6 +280,31 @@ protected static function isMongodbInstance(GraphqlType $parentType): bool
         return isset($parentType->config['model']) ? app($parentType->config['model']) instanceof $mongoType : false;
     }
 
+    /**
+     * Get types from UnionType or InterfaceType.
+     *
+     * @return GraphqlType[]
+     */
+    protected static function getTypesFromUnionOrInterface(GraphqlType $type): array
+    {
+        if ($type instanceof UnionType) {
+            return $type->getTypes();
+        }
+
+        if ($type instanceof \GraphQL\Type\Definition\InterfaceType) {
+            // For InterfaceType, get types from the config
+            // @phpstan-ignore-next-line - InterfaceType can have custom 'types' config
+            if (isset($type->config['types']) && \is_callable($type->config['types'])) {
+                /** @var callable(): array<int, GraphqlType> $typesCallable */
+                $typesCallable = $type->config['types'];
+
+                return $typesCallable();
+            }
+        }
+
+        return [];
+    }
+
     /**
      * @param string|Expression $field
      * @param array $select Passed by reference, adds further fields to select
@@ -451,6 +491,23 @@ protected static function handleInterfaceFields(
     ): void {
         $relationsKey = Arr::get($fieldObject->config, 'alias', $key);
 
+        // Check if this field is actually a relation
+        $queryable = static::isQueryable($fieldObject->config);
+        $isRelation = $queryable && \is_array($field['fields']) && !empty($field['fields']);
+
+        // If it's not a relation, handle it as a regular field
+        if (!$isRelation) {
+            // @phpstan-ignore-next-line - Custom config key
+            $key = $fieldObject->config['alias'] ?? $key;
+            // @phpstan-ignore-next-line - alias can be Closure or string
+            $key = $key instanceof Closure ? $key() : $key;
+            $parentTable = static::isMongodbInstance($parentType) ? null : static::getTableNameFromParentType($parentType);
+            static::addFieldToSelect($key, $select, $parentTable, false);
+            static::addAlwaysFields($fieldObject, $select, $parentTable);
+
+            return;
+        }
+
         $with[$relationsKey] = function ($query) use (
             $queryArgs,
             $field,
@@ -461,6 +518,11 @@ protected static function handleInterfaceFields(
             $key,
             $fieldObject
         ) {
+            // Check if $query is actually a relation
+            if (!($query instanceof Relation)) {
+                return $query;
+            }
+
             $parentTable = static::isMongodbInstance($parentType) ? null : static::getTableNameFromParentType($parentType);
 
             static::handleRelation($select, $query, $parentTable, $field);
@@ -518,6 +580,93 @@ function (GraphqlType $type) use ($query) {
         };
     }
 
+    /**
+     * Handle MorphTo relations
+     * @param mixed $ctx
+     */
+    protected static function handleMorphToRelation(
+        array $queryArgs,
+        array $field,
+        array &$with,
+        $ctx,
+        FieldDefinition $fieldObject,
+        string $key,
+        ?Closure $customQuery
+    ): void {
+        $relationsKey = Arr::get($fieldObject->config, 'alias', $key);
+
+        /* @var GraphqlType $fieldType */
+        $fieldType = $fieldObject->config['type'];
+
+        if ($fieldType instanceof WrappingType) {
+            $fieldType = $fieldType->getInnermostType();
+        }
+
+        $relationNames = (isset($fieldType->config['relationName']) && \is_callable($fieldType->config['relationName']))
+            ? $fieldType->config['relationName']()
+            : null;
+
+        // @phpstan-ignore-next-line - getInnermostType returns Type which is GraphqlType
+        $types = static::getTypesFromUnionOrInterface($fieldType);
+        $isInterface = $fieldType instanceof \GraphQL\Type\Definition\InterfaceType;
+
+        $with[$relationsKey] = function ($relation) use ($queryArgs, $field, $types, $relationNames, $customQuery, $ctx, $isInterface) {
+            // Check if $relation is actually a MorphTo relation
+            if (!($relation instanceof MorphTo)) {
+                return $relation;
+            }
+
+            $morphRelation = [];
+
+            foreach ($types as $type) {
+                // Get the model class name for the morph type
+                if (isset($type->config['model'])) {
+                    $modelClass = $type->config['model'];
+                } else {
+                    // Fallback to type name if no model is configured
+                    $typeName = $type instanceof \GraphQL\Type\Definition\NamedType ? $type->name() : '';
+                    $modelClass = $relationNames[$typeName] ?? $typeName;
+                }
+
+                /** @var callable $callable */
+                $callable = static::getSelectableFieldsAndRelations(
+                    $queryArgs,
+                    $field,
+                    $type,
+                    $customQuery,
+                    false,
+                    $ctx
+                );
+
+                // If the field type is an interface, wrap the callable to select * instead
+                // This is necessary because interfaces can have different implementations
+                // with different fields, so we need to select all fields
+                if ($isInterface) {
+                    $originalCallable = $callable;
+                    $callable = function ($query) use ($originalCallable) {
+                        // Call the original callable first to set up relations
+                        $originalCallable($query);
+                        // Override select to use * for interface types
+                        // We need to clear existing columns and set to * to ensure
+                        // all fields from the concrete type are selected
+                        $query->getQuery()->columns = null;
+                        $query->select('*');
+
+                        return $query;
+                    };
+                }
+
+                $morphRelation[$modelClass] = $callable;
+            }
+
+            if (!empty($morphRelation)) {
+                $relation->constrain($morphRelation);
+            }
+
+            return $relation;
+        };
+    }
+
     public function getSelect(): array
     {
         return $this->select;
diff --git a/src/Support/UnionType.php b/src/Support/UnionType.php
index 7f13fe8b..955c1ab8 100644
--- a/src/Support/UnionType.php
+++ b/src/Support/UnionType.php
@@ -30,6 +30,10 @@ public function getAttributes(): array
             $attributes['resolveType'] = [$this, 'resolveType'];
         }
 
+        if (method_exists($this, 'relationName')) {
+            $attributes['relationName'] = [$this, 'relationName'];
+        }
+
         return $attributes;
     }
 
diff --git a/tests/Database/SelectFields/UnionMorphTests/CommentType.php b/tests/Database/SelectFields/UnionMorphTests/CommentType.php
new file mode 100644
index 00000000..80f96698
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/CommentType.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\Type as GraphQLType;
+use Rebing\GraphQL\Tests\Support\Models\Comment;
+
+class CommentType extends GraphQLType
+{
+    protected $attributes = [
+        'name' => 'Comment',
+        'model' => Comment::class,
+    ];
+
+    public function fields(): array
+    {
+        return [
+            'id' => [
+                'type' => Type::nonNull(Type::id()),
+            ],
+            'title' => [
+                'type' => Type::nonNull(Type::string()),
+            ],
+            'body' => [
+                'type' => Type::string(),
+            ],
+            'file' => [
+                'type' => GraphQL::type('File'),
+            ],
+            'commentable' => [
+                'type' => GraphQL::type('CommentableUnion'),
+            ],
+        ];
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/CommentableUnionType.php b/tests/Database/SelectFields/UnionMorphTests/CommentableUnionType.php
new file mode 100644
index 00000000..0858c6dc
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/CommentableUnionType.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type as GraphqlType;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\UnionType;
+use Rebing\GraphQL\Tests\Support\Models\Post;
+use Rebing\GraphQL\Tests\Support\Models\Product;
+
+class CommentableUnionType extends UnionType
+{
+    protected $attributes = [
+        'name' => 'CommentableUnion',
+    ];
+
+    public function types(): array
+    {
+        return [
+            GraphQL::type('Post'),
+            GraphQL::type('Product'),
+        ];
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function relationName(): array
+    {
+        return [
+            Post::class => 'post',
+            Product::class => 'product',
+        ];
+    }
+
+    public function resolveType(object $value): ?GraphqlType
+    {
+        if ($value instanceof Post) {
+            return GraphQL::type('Post');
+        }
+
+        if ($value instanceof Product) {
+            return GraphQL::type('Product');
+        }
+
+        return null;
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php b/tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
new file mode 100644
index 00000000..1c4bfe85
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/CommentsQuery.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use Closure;
+use GraphQL\Type\Definition\ResolveInfo;
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\Query;
+use Rebing\GraphQL\Support\SelectFields;
+use Rebing\GraphQL\Tests\Support\Models\Comment;
+
+class CommentsQuery extends Query
+{
+    protected $attributes = [
+        'name' => 'comments',
+    ];
+
+    public function type(): Type
+    {
+        return Type::listOf(GraphQL::type('Comment'));
+    }
+
+    public function resolve($root, $args, $context, ResolveInfo $info, Closure $getSelectFields): array|\Illuminate\Database\Eloquent\Collection
+    {
+        /** @var SelectFields $selectFields */
+        $selectFields = $getSelectFields();
+
+        return Comment::query()
+            ->select($selectFields->getSelect())
+            ->with($selectFields->getRelations())
+            ->get();
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/FileType.php b/tests/Database/SelectFields/UnionMorphTests/FileType.php
new file mode 100644
index 00000000..0cab9b86
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/FileType.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\Type as GraphQLType;
+use Rebing\GraphQL\Tests\Support\Models\File;
+
+class FileType extends GraphQLType
+{
+    protected $attributes = [
+        'name' => 'File',
+        'model' => File::class,
+    ];
+
+    public function fields(): array
+    {
+        return [
+            'id' => [
+                'type' => Type::nonNull(Type::id()),
+            ],
+            'name' => [
+                'type' => Type::string(),
+            ],
+            'path' => [
+                'type' => Type::string(),
+            ],
+            'folder' => [
+                'type' => GraphQL::type('Folder'),
+            ],
+        ];
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/FolderType.php b/tests/Database/SelectFields/UnionMorphTests/FolderType.php
new file mode 100644
index 00000000..aefdd7f3
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/FolderType.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Type as GraphQLType;
+use Rebing\GraphQL\Tests\Support\Models\Folder;
+
+class FolderType extends GraphQLType
+{
+    protected $attributes = [
+        'name' => 'Folder',
+        'model' => Folder::class,
+    ];
+
+    public function fields(): array
+    {
+        return [
+            'id' => [
+                'type' => Type::nonNull(Type::id()),
+            ],
+            'name' => [
+                'type' => Type::string(),
+            ],
+        ];
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/PostType.php b/tests/Database/SelectFields/UnionMorphTests/PostType.php
new file mode 100644
index 00000000..57df053d
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/PostType.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\Type as GraphQLType;
+use Rebing\GraphQL\Tests\Support\Models\Post;
+
+class PostType extends GraphQLType
+{
+    protected $attributes = [
+        'name' => 'Post',
+        'model' => Post::class,
+    ];
+
+    public function fields(): array
+    {
+        return [
+            'id' => [
+                'type' => Type::nonNull(Type::id()),
+            ],
+            'title' => [
+                'type' => Type::string(),
+            ],
+            'file' => [
+                'type' => GraphQL::type('File'),
+            ],
+        ];
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/ProductType.php b/tests/Database/SelectFields/UnionMorphTests/ProductType.php
new file mode 100644
index 00000000..45aacdb6
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/ProductType.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use GraphQL\Type\Definition\Type;
+use Rebing\GraphQL\Support\Facades\GraphQL;
+use Rebing\GraphQL\Support\Type as GraphQLType;
+use Rebing\GraphQL\Tests\Support\Models\Product;
+
+class ProductType extends GraphQLType
+{
+    protected $attributes = [
+        'name' => 'Product',
+        'model' => Product::class,
+    ];
+
+    public function fields(): array
+    {
+        return [
+            'id' => [
+                'type' => Type::nonNull(Type::id()),
+            ],
+            'name' => [
+                'type' => Type::string(),
+            ],
+            'price' => [
+                'type' => Type::int(),
+            ],
+            'file' => [
+                'type' => GraphQL::type('File'),
+            ],
+        ];
+    }
+}
diff --git a/tests/Database/SelectFields/UnionMorphTests/UnionMorphTest.php b/tests/Database/SelectFields/UnionMorphTests/UnionMorphTest.php
new file mode 100644
index 00000000..1f154ed4
--- /dev/null
+++ b/tests/Database/SelectFields/UnionMorphTests/UnionMorphTest.php
@@ -0,0 +1,236 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Database\SelectFields\UnionMorphTests;
+
+use Illuminate\Database\Eloquent\Model;
+use Rebing\GraphQL\Tests\Support\Models\Comment;
+use Rebing\GraphQL\Tests\Support\Models\File;
+use Rebing\GraphQL\Tests\Support\Models\Folder;
+use Rebing\GraphQL\Tests\Support\Models\Post;
+use Rebing\GraphQL\Tests\Support\Models\Product;
+use Rebing\GraphQL\Tests\Support\Models\User;
+use Rebing\GraphQL\Tests\Support\Traits\SqlAssertionTrait;
+use Rebing\GraphQL\Tests\TestCaseDatabase;
+
+class UnionMorphTest extends TestCaseDatabase
+{
+    use SqlAssertionTrait;
+
+    protected function getEnvironmentSetUp($app): void
+    {
+        parent::getEnvironmentSetUp($app);
+
+        $app['config']->set('graphql.schemas.default', [
+            'query' => [
+              CommentsQuery::class,
+            ],
+        ]);
+
+        $app['config']->set('graphql.types', [
+            FileType::class,
+            FolderType::class,
+            PostType::class,
+            ProductType::class,
+            CommentableUnionType::class,
+            CommentType::class,
+        ]);
+
+        Model::preventLazyLoading();
+    }
+
+    public function testUnionMorphEagerLoading(): void
+    {
+        // Create 2 products with different files and product folder
+        /** @var Folder $productFolder */
+        $productFolder = Folder::factory()->create(['name' => 'product']);
+
+        /** @var File $productFile1 */
+        $productFile1 = File::factory()->create(['folder_id' => $productFolder->id, 'name' => 'product_file_1.pdf']);
+
+        /** @var File $productFile2 */
+        $productFile2 = File::factory()->create(['folder_id' => $productFolder->id, 'name' => 'product_file_2.jpg']);
+
+        /** @var Product $product1 */
+        $product1 = Product::factory()->create(['file_id' => $productFile1->id, 'name' => 'Product 1']);
+
+        /** @var Product $product2 */
+        $product2 = Product::factory()->create(['file_id' => $productFile2->id, 'name' => 'Product 2']);
+
+        // Create 2 posts with different files and post folder
+        /** @var User $user */
+        $user = User::factory()->create();
+
+        /** @var Folder $postFolder */
+        $postFolder = Folder::factory()->create(['name' => 'post']);
+
+        /** @var File $postFile1 */
+        $postFile1 = File::factory()->create(['folder_id' => $postFolder->id, 'name' => 'post_file_1.docx']);
+
+        /** @var File $postFile2 */
+        $postFile2 = File::factory()->create(['folder_id' => $postFolder->id, 'name' => 'post_file_2.png']);
+
+        /** @var Post $post1 */
+        $post1 = Post::factory()->create(['user_id' => $user->id, 'file_id' => $postFile1->id, 'title' => 'Post 1']);
+
+        /** @var Post $post2 */
+        $post2 = Post::factory()->create(['user_id' => $user->id, 'file_id' => $postFile2->id, 'title' => 'Post 2']);
+
+        // Create comments for all products and posts using morphable relationships
+        /** @var Comment $product1Comment */
+        $product1Comment = Comment::factory()->create();
+        $product1->commentableComments()->save($product1Comment);
+
+        /** @var Comment $product2Comment */
+        $product2Comment = Comment::factory()->create();
+        $product2->commentableComments()->save($product2Comment);
+
+        /** @var Comment $post1Comment */
+        $post1Comment = Comment::factory()->create();
+        $post1->commentableComments()->save($post1Comment);
+
+        /** @var Comment $post2Comment */
+        $post2Comment = Comment::factory()->create();
+        $post2->commentableComments()->save($post2Comment);
+
+        $query =
+/** @lang GraphQL */ <<<'GRAQPHQL'
+{
+  comments {
+    id
+    title
+    body
+    commentable {
+      ... on Post {
+        id
+        title
+        file {
+          id
+          name
+          path
+          folder {
+            id
+            name
+          }
+        }
+      }
+      ... on Product {
+        id
+        name
+        price
+        file {
+          id
+          name
+          path
+          folder {
+            id
+            name
+          }
+        }
+      }
+    }
+  }
+}
+GRAQPHQL;
+
+        $this->sqlCounterReset();
+
+        $result = $this->httpGraphql($query);
+
+        $this->assertSqlQueries(
+            /** @lang SQL */
+            <<<'SQL'
+select "comments"."id", "comments"."title", "comments"."body", "comments"."commentable_id", "comments"."commentable_type" from "comments";
+select "products"."id", "products"."name", "products"."price", "products"."file_id" from "products" where "products"."id" in (?, ?);
+select "files"."id", "files"."name", "files"."path", "files"."folder_id" from "files" where "files"."id" in (?, ?);
+select "folders"."id", "folders"."name" from "folders" where "folders"."id" in (?);
+select "posts"."id", "posts"."file_id", "posts"."title" from "posts" where "posts"."id" in (?, ?);
+select "files"."id", "files"."name", "files"."path", "files"."folder_id" from "files" where "files"."id" in (?, ?);
+select "folders"."id", "folders"."name" from "folders" where "folders"."id" in (?);
+SQL
+        );
+
+        $expectedResult = [
+            'data' => [
+                'comments' => [
+                    [
+                        'id' => (string) $product1Comment->id,
+                        'title' => $product1Comment->title,
+                        'body' => $product1Comment->body,
+                        'commentable' => [
+                            'id' => (string) $product1->id,
+                            'name' => $product1->name,
+                            'price' => $product1->price,
+                            'file' => [
+                                'id' => (string) $productFile1->id,
+                                'name' => $productFile1->name,
+                                'path' => $productFile1->path,
+                                'folder' => [
+                                    'id' => (string) $productFolder->id,
+                                    'name' => $productFolder->name,
+                                ],
+                            ],
+                        ],
+                    ],
+                    [
+                        'id' => (string) $product2Comment->id,
+                        'title' => $product2Comment->title,
+                        'body' => $product2Comment->body,
+                        'commentable' => [
+                            'id' => (string) $product2->id,
+                            'name' => $product2->name,
+                            'price' => $product2->price,
+                            'file' => [
+                                'id' => (string) $productFile2->id,
+                                'name' => $productFile2->name,
+                                'path' => $productFile2->path,
+                                'folder' => [
+                                    'id' => (string) $productFolder->id,
+                                    'name' => $productFolder->name,
+                                ],
+                            ],
+                        ],
+                    ],
+                    [
+                        'id' => (string) $post1Comment->id,
+                        'title' => $post1Comment->title,
+                        'body' => $post1Comment->body,
+                        'commentable' => [
+                            'id' => (string) $post1->id,
+                            'title' => $post1->title,
+                            'file' => [
+                                'id' => (string) $postFile1->id,
+                                'name' => $postFile1->name,
+                                'path' => $postFile1->path,
+                                'folder' => [
+                                    'id' => (string) $postFolder->id,
+                                    'name' => $postFolder->name,
+                                ],
+                            ],
+                        ],
+                    ],
+                    [
+                        'id' => (string) $post2Comment->id,
+                        'title' => $post2Comment->title,
+                        'body' => $post2Comment->body,
+                        'commentable' => [
+                            'id' => (string) $post2->id,
+                            'title' => $post2->title,
+                            'file' => [
+                                'id' => (string) $postFile2->id,
+                                'name' => $postFile2->name,
+                                'path' => $postFile2->path,
+                                'folder' => [
+                                    'id' => (string) $postFolder->id,
+                                    'name' => $postFolder->name,
+                                ],
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ];
+
+        self::assertSame($expectedResult, $result);
+    }
+}
diff --git a/tests/Support/Models/Comment.php b/tests/Support/Models/Comment.php
index ef66191e..ace15198 100644
--- a/tests/Support/Models/Comment.php
+++ b/tests/Support/Models/Comment.php
@@ -9,6 +9,7 @@
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
 use Rebing\GraphQL\Tests\Support\database\factories\CommentFactory;
 
 /**
@@ -17,7 +18,7 @@
  * @property string $title
  * @property string|null $body
  * @property bool $flag
- * @property-read Post $post
+ * @property-read Post              $post
  * @property-read Collection|Like[] $likes
  */
 class Comment extends Model
@@ -34,6 +35,11 @@ public function likes(): MorphMany
         return $this->morphMany(Like::class, 'likable');
     }
 
+    public function commentable(): MorphTo
+    {
+        return $this->morphTo();
+    }
+
     protected static function newFactory(): Factory
     {
         return CommentFactory::new();
diff --git a/tests/Support/Models/File.php b/tests/Support/Models/File.php
new file mode 100644
index 00000000..3642ed5f
--- /dev/null
+++ b/tests/Support/Models/File.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\Models;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Rebing\GraphQL\Tests\Support\database\factories\FileFactory;
+
+/**
+ * @property int $id
+ * @property string $name
+ * @property string $path
+ * @property int|null $folder_id
+ * @property string|null $fileable_type
+ * @property int|null $fileable_id
+ */
+class File extends Model
+{
+    use HasFactory;
+
+    /** @var string[] */
+    protected $guarded = [];
+
+    protected static function newFactory(): Factory
+    {
+        return FileFactory::new();
+    }
+
+    public function folder(): BelongsTo
+    {
+        return $this->belongsTo(Folder::class);
+    }
+}
diff --git a/tests/Support/Models/Folder.php b/tests/Support/Models/Folder.php
new file mode 100644
index 00000000..37a00e75
--- /dev/null
+++ b/tests/Support/Models/Folder.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\Models;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Rebing\GraphQL\Tests\Support\database\factories\FolderFactory;
+
+/**
+ * @property int $id
+ * @property string $name
+ */
+class Folder extends Model
+{
+    use HasFactory;
+
+    /** @var string[] */
+    protected $guarded = [];
+
+    public function files(): HasMany
+    {
+        return $this->hasMany(File::class);
+    }
+
+    protected static function newFactory(): Factory
+    {
+        return FolderFactory::new();
+    }
+}
diff --git a/tests/Support/Models/Post.php b/tests/Support/Models/Post.php
index 538823ba..f5e77b62 100644
--- a/tests/Support/Models/Post.php
+++ b/tests/Support/Models/Post.php
@@ -24,6 +24,7 @@
  * @property bool $is_published
  * @property-read Collection|Comment[] $comments
  * @property-read Collection|Like[] $likes
+ * @property-read Collection|File[] $files
  */
 class Post extends Model
 {
@@ -49,6 +50,16 @@ public function comments(): HasMany
         return $this->hasMany(Comment::class)->orderBy('comments.id');
     }
 
+    public function commentableComments(): MorphMany
+    {
+        return $this->morphMany(Comment::class, 'commentable');
+    }
+
+    public function file(): BelongsTo
+    {
+        return $this->belongsTo(File::class, 'file_id');
+    }
+
     public function likes(): MorphMany
     {
         return $this->morphMany(Like::class, 'likable');
diff --git a/tests/Support/Models/Product.php b/tests/Support/Models/Product.php
new file mode 100644
index 00000000..9bdb52ec
--- /dev/null
+++ b/tests/Support/Models/Product.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\Models;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphMany;
+use Illuminate\Support\Carbon;
+use Rebing\GraphQL\Tests\Support\database\factories\ProductFactory;
+
+/**
+ * @property int $id
+ * @property string $name
+ * @property float|null $price
+ * @property Carbon|null $published_at
+ * @property bool $is_published
+ * @property-read File|null $file
+ */
+class Product extends Model
+{
+    use HasFactory;
+
+    /** @var string[] */
+    protected $dates = [
+        'published_at',
+    ];
+
+    public function file(): BelongsTo
+    {
+        return $this->belongsTo(File::class, 'file_id');
+    }
+
+    public function commentableComments(): MorphMany
+    {
+        return $this->morphMany(Comment::class, 'commentable');
+    }
+
+    public function getIsPublishedAttribute(): bool
+    {
+        $publishedAt = $this->published_at;
+
+        return null !== $publishedAt;
+    }
+
+    protected static function newFactory(): Factory
+    {
+        return ProductFactory::new();
+    }
+}
diff --git a/tests/Support/database/factories/FileFactory.php b/tests/Support/database/factories/FileFactory.php
new file mode 100644
index 00000000..86a15851
--- /dev/null
+++ b/tests/Support/database/factories/FileFactory.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\database\factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Rebing\GraphQL\Tests\Support\Models\File;
+
+class FileFactory extends Factory
+{
+    protected $model = File::class;
+
+    public function definition(): array
+    {
+        return [
+            'name' => $this->faker->word() . '.txt',
+            'path' => '/files/' . $this->faker->word(),
+            'folder_id' => null,
+        ];
+    }
+}
diff --git a/tests/Support/database/factories/FolderFactory.php b/tests/Support/database/factories/FolderFactory.php
new file mode 100644
index 00000000..240c5488
--- /dev/null
+++ b/tests/Support/database/factories/FolderFactory.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\database\factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Rebing\GraphQL\Tests\Support\Models\Folder;
+
+class FolderFactory extends Factory
+{
+    protected $model = Folder::class;
+
+    public function definition(): array
+    {
+        return [
+            'name' => $this->faker->word(),
+        ];
+    }
+}
diff --git a/tests/Support/database/factories/ProductFactory.php b/tests/Support/database/factories/ProductFactory.php
new file mode 100644
index 00000000..91261266
--- /dev/null
+++ b/tests/Support/database/factories/ProductFactory.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types = 1);
+namespace Rebing\GraphQL\Tests\Support\database\factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Rebing\GraphQL\Tests\Support\Models\Product;
+
+/**
+ * @extends Factory<Product>
+ */
+class ProductFactory extends Factory
+{
+    protected $model = Product::class;
+
+    public function definition(): array
+    {
+        return [
+            'name' => fake()->words(3, true),
+            'price' => fake()->numberBetween(100, 1_000_000),
+        ];
+    }
+}
diff --git a/tests/Support/database/migrations/____comments_table.php b/tests/Support/database/migrations/____comments_table.php
index 959f35dc..b1b65c9c 100644
--- a/tests/Support/database/migrations/____comments_table.php
+++ b/tests/Support/database/migrations/____comments_table.php
@@ -12,7 +12,8 @@ public function up(): void
     {
         Schema::create('comments', function (Blueprint $table): void {
             $table->increments('id');
-            $table->integer('post_id');
+            $table->integer('post_id')->nullable();
+            $table->nullableMorphs('commentable');
             $table->string('title');
             $table->string('body')->nullable();
             $table->boolean('flag')->default('false');
diff --git a/tests/Support/database/migrations/____files_table.php b/tests/Support/database/migrations/____files_table.php
new file mode 100644
index 00000000..84fa78e5
--- /dev/null
+++ b/tests/Support/database/migrations/____files_table.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types = 1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class FilesTable extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('files', function (Blueprint $table): void {
+            $table->increments('id');
+            $table->unsignedInteger('folder_id')->nullable();
+            $table->string('name');
+            $table->string('path');
+            $table->unsignedInteger('size')->default(0);
+            $table->timestamps();
+        });
+    }
+}
diff --git a/tests/Support/database/migrations/____folders_table.php b/tests/Support/database/migrations/____folders_table.php
new file mode 100644
index 00000000..880c8d5e
--- /dev/null
+++ b/tests/Support/database/migrations/____folders_table.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types = 1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class FoldersTable extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('folders', function (Blueprint $table): void {
+            $table->increments('id');
+            $table->string(column: 'name');
+            $table->unsignedInteger('parent_id')->nullable();
+            $table->timestamps();
+        });
+    }
+}
diff --git a/tests/Support/database/migrations/____posts_table.php b/tests/Support/database/migrations/____posts_table.php
index 8c5ad33d..9a57210c 100644
--- a/tests/Support/database/migrations/____posts_table.php
+++ b/tests/Support/database/migrations/____posts_table.php
@@ -17,6 +17,7 @@ public function up(): void
             $table->integer('user_id')->nullable();
             $table->text('properties')->nullable();
             $table->boolean('flag')->default('false');
+            $table->unsignedInteger('file_id')->nullable();
             $table->dateTime('published_at')->nullable();
             $table->timestamps();
         });
diff --git a/tests/Support/database/migrations/____products_table.php b/tests/Support/database/migrations/____products_table.php
new file mode 100644
index 00000000..3a846328
--- /dev/null
+++ b/tests/Support/database/migrations/____products_table.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types = 1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class ProductsTable extends Migration
+{
+    public function up(): void
+    {
+        Schema::create('products', function (Blueprint $table): void {
+            $table->increments('id');
+            $table->string('name');
+            $table->decimal('price', 10, 2)->nullable();
+            $table->unsignedInteger('file_id')->nullable();
+            $table->dateTime(column: 'published_at')->nullable();
+            $table->timestamps();
+        });
+    }
+}