diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/misc.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/misc.scala
index 6f806760b3736..3507627a58571 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/misc.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/misc.scala
@@ -97,6 +97,21 @@ case class RaiseError(errorClass: Expression, errorParms: Expression, dataType:
 
   override def prettyName: String = "raise_error"
 
+  override def sql: String = {
+    // When constructed from the single-argument form (just an error message string),
+    // output only the original message to produce valid, roundtrippable SQL.
+    (errorClass, errorParms) match {
+      case (Literal(cls, _), CreateMap(Seq(Literal(key, _), msg), _))
+        if cls != null &&
+          (cls.toString == "USER_RAISED_EXCEPTION" ||
+            cls.toString == "_LEGACY_ERROR_USER_RAISED_EXCEPTION") &&
+          key != null && key.toString == "errorMessage" =>
+        s"$prettyName(${msg.sql})"
+      case _ =>
+        super.sql
+    }
+  }
+
   override def eval(input: InternalRow): Any = {
     val error = errorClass.eval(input).asInstanceOf[UTF8String]
     val parms: MapData = errorParms.eval(input).asInstanceOf[MapData]
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MiscExpressionsSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MiscExpressionsSuite.scala
index 40e6fe1a90a63..ff0183eb265b8 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MiscExpressionsSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/MiscExpressionsSuite.scala
@@ -55,6 +55,16 @@ class MiscExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
     )
   }
 
+  test("SPARK-55109: RaiseError.sql uses single-argument form only for known error classes") {
+    assert(RaiseError(Literal("error!")).sql === "raise_error('error!')")
+
+    // A custom errorClass should NOT produce the single-argument form
+    val customError = RaiseError(
+      Literal("CUSTOM_ERROR"),
+      CreateMap(Seq(Literal("errorMessage"), Literal("error!"))))
+    assert(customError.sql === "raise_error('CUSTOM_ERROR', map('errorMessage', 'error!'))")
+  }
+
   test("uuid") {
     checkEvaluation(Length(Uuid(Some(0))), 36)
     val r = new Random()