diff --git a/packages/material-ui/src/FormControl/useFormControl.d.ts b/packages/material-ui/src/FormControl/useFormControl.d.ts
index 493cff9159bb23..ab0e95221880f3 100644
--- a/packages/material-ui/src/FormControl/useFormControl.d.ts
+++ b/packages/material-ui/src/FormControl/useFormControl.d.ts
@@ -23,4 +23,4 @@ export interface FormControlState extends Pick<FormControlProps, ContextFromProp
   onFocus: () => void;
 }
 
-export default function useFormControl(): FormControlState;
+export default function useFormControl(): FormControlState | undefined;
diff --git a/packages/material-ui/src/RadioGroup/useRadioGroup.d.ts b/packages/material-ui/src/RadioGroup/useRadioGroup.d.ts
index 3afca97c318e19..ae3fa093db4b42 100644
--- a/packages/material-ui/src/RadioGroup/useRadioGroup.d.ts
+++ b/packages/material-ui/src/RadioGroup/useRadioGroup.d.ts
@@ -3,4 +3,4 @@ import { RadioGroupProps } from './RadioGroup';
 
 export interface RadioGroupState extends Pick<RadioGroupProps, 'name' | 'onChange' | 'value'> {}
 
-export default function useRadioGroup(): RadioGroupState;
+export default function useRadioGroup(): RadioGroupState | undefined;