diff --git a/packages/mui-material/src/Checkbox/Checkbox.js b/packages/mui-material/src/Checkbox/Checkbox.js
index b2e74924e5dea6..14801354fb65cf 100644
--- a/packages/mui-material/src/Checkbox/Checkbox.js
+++ b/packages/mui-material/src/Checkbox/Checkbox.js
@@ -171,6 +171,10 @@ const Checkbox = React.forwardRef(function Checkbox(inProps, ref) {
             : externalInputProps,
           {
             'data-indeterminate': indeterminate,
+            ...(indeterminate && {
+              // https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-checked#values
+              'aria-checked': 'mixed',
+            }),
           },
         ),
       },
diff --git a/packages/mui-material/src/Checkbox/Checkbox.test.js b/packages/mui-material/src/Checkbox/Checkbox.test.js
index 49599c9108aede..8f53f4a2c4f4fc 100644
--- a/packages/mui-material/src/Checkbox/Checkbox.test.js
+++ b/packages/mui-material/src/Checkbox/Checkbox.test.js
@@ -80,6 +80,11 @@ describe('<Checkbox />', () => {
       const { getByTestId } = render(<Checkbox indeterminate />);
       expect(getByTestId('IndeterminateCheckBoxIcon')).not.to.equal(null);
     });
+
+    it('should have aria-checked="mixed"', () => {
+      const { getByRole } = render(<Checkbox indeterminate />);
+      expect(getByRole('checkbox')).to.have.attribute('aria-checked', 'mixed');
+    });
   });
 
   describe('prop: size', () => {