diff --git a/reports/api-extractor.md b/reports/api-extractor.md
index ed30b418e61..bdeb498a821 100644
--- a/reports/api-extractor.md
+++ b/reports/api-extractor.md
@@ -37,7 +37,7 @@ export type ChangeHandler = (event: {
 }) => Promise<void | boolean>;
 
 // @public (undocumented)
-export type Control<TFieldValues extends FieldValues = FieldValues, TContext = any> = {
+export type Control<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues = TFieldValues> = {
     _subjects: Subjects<TFieldValues>;
     _removeUnmounted: Noop;
     _names: Names;
@@ -76,7 +76,7 @@ export type Control<TFieldValues extends FieldValues = FieldValues, TContext = a
         errors: FieldErrors;
     }>;
     register: UseFormRegister<TFieldValues>;
-    handleSubmit: UseFormHandleSubmit<TFieldValues>;
+    handleSubmit: UseFormHandleSubmit<TFieldValues, TTransformedValues>;
     _disableForm: (disabled?: boolean) => void;
     unregister: UseFormUnregister<TFieldValues>;
     getFieldState: UseFormGetFieldState<TFieldValues>;
@@ -286,10 +286,10 @@ export type FormProps<TFieldValues extends FieldValues, TTransformedValues exten
 }>;
 
 // @public
-export const FormProvider: <TFieldValues extends FieldValues, TContext = any, TTransformedValues extends FieldValues | undefined = undefined>(props: FormProviderProps<TFieldValues, TContext, TTransformedValues>) => React_2.JSX.Element;
+export const FormProvider: <TFieldValues extends FieldValues, TContext = any, TTransformedValues extends FieldValues = TFieldValues>(props: FormProviderProps<TFieldValues, TContext, TTransformedValues>) => React_2.JSX.Element;
 
 // @public (undocumented)
-export type FormProviderProps<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues | undefined = undefined> = {
+export type FormProviderProps<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues = TFieldValues> = {
     children: React_2.ReactNode | React_2.ReactNode[];
 } & UseFormReturn<TFieldValues, TContext, TTransformedValues>;
 
@@ -650,13 +650,13 @@ export type UseFieldArraySwap = (indexA: number, indexB: number) => void;
 export type UseFieldArrayUpdate<TFieldValues extends FieldValues, TFieldArrayName extends FieldArrayPath<TFieldValues> = FieldArrayPath<TFieldValues>> = (index: number, value: FieldArray<TFieldValues, TFieldArrayName>) => void;
 
 // @public
-export function useForm<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues | undefined = undefined>(props?: UseFormProps<TFieldValues, TContext>): UseFormReturn<TFieldValues, TContext, TTransformedValues>;
+export function useForm<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues = TFieldValues>(props?: UseFormProps<TFieldValues, TContext>): UseFormReturn<TFieldValues, TContext, TTransformedValues>;
 
 // @public
 export type UseFormClearErrors<TFieldValues extends FieldValues> = (name?: FieldPath<TFieldValues> | FieldPath<TFieldValues>[] | readonly FieldPath<TFieldValues>[] | `root.${string}` | 'root') => void;
 
 // @public
-export const useFormContext: <TFieldValues extends FieldValues, TContext = any, TransformedValues extends FieldValues | undefined = undefined>() => UseFormReturn<TFieldValues, TContext, TransformedValues>;
+export const useFormContext: <TFieldValues extends FieldValues, TContext = any, TransformedValues extends FieldValues = TFieldValues>() => UseFormReturn<TFieldValues, TContext, TransformedValues>;
 
 // @public
 export type UseFormGetFieldState<TFieldValues extends FieldValues> = <TFieldName extends FieldPath<TFieldValues>>(name: TFieldName, formState?: FormState<TFieldValues>) => {
@@ -674,7 +674,7 @@ export type UseFormGetValues<TFieldValues extends FieldValues> = {
 };
 
 // @public
-export type UseFormHandleSubmit<TFieldValues extends FieldValues, TTransformedValues extends FieldValues | undefined = undefined> = (onValid: TTransformedValues extends undefined ? SubmitHandler<TFieldValues> : TTransformedValues extends FieldValues ? SubmitHandler<TTransformedValues> : never, onInvalid?: SubmitErrorHandler<TFieldValues>) => (e?: React_2.BaseSyntheticEvent) => Promise<void>;
+export type UseFormHandleSubmit<TFieldValues extends FieldValues, TTransformedValues extends FieldValues = TFieldValues> = (onValid: SubmitHandler<TTransformedValues>, onInvalid?: SubmitErrorHandler<TFieldValues>) => (e?: React_2.BaseSyntheticEvent) => Promise<void>;
 
 // @public (undocumented)
 export type UseFormProps<TFieldValues extends FieldValues = FieldValues, TContext = any> = Partial<{
@@ -727,7 +727,7 @@ export type UseFormResetField<TFieldValues extends FieldValues> = <TFieldName ex
 }>) => void;
 
 // @public (undocumented)
-export type UseFormReturn<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues | undefined = undefined> = {
+export type UseFormReturn<TFieldValues extends FieldValues = FieldValues, TContext = any, TTransformedValues extends FieldValues = TFieldValues> = {
     watch: UseFormWatch<TFieldValues>;
     getValues: UseFormGetValues<TFieldValues>;
     getFieldState: UseFormGetFieldState<TFieldValues>;
@@ -740,7 +740,7 @@ export type UseFormReturn<TFieldValues extends FieldValues = FieldValues, TConte
     reset: UseFormReset<TFieldValues>;
     handleSubmit: UseFormHandleSubmit<TFieldValues, TTransformedValues>;
     unregister: UseFormUnregister<TFieldValues>;
-    control: Control<TFieldValues, TContext>;
+    control: Control<TFieldValues, TContext, TTransformedValues>;
     register: UseFormRegister<TFieldValues>;
     setFocus: UseFormSetFocus<TFieldValues>;
 };
diff --git a/src/__typetest__/form.test-d.ts b/src/__typetest__/form.test-d.ts
index b795c3e2552..0a65b0f5f7e 100644
--- a/src/__typetest__/form.test-d.ts
+++ b/src/__typetest__/form.test-d.ts
@@ -25,6 +25,23 @@ import { useForm } from '../useForm';
 
     handleSubmit((data) => expectType<{ test: string; test1: number }>(data));
   }
+
+  /** it should infer the correct TTransformedValues from useForm generic */ {
+    /* eslint-disable react-hooks/rules-of-hooks */
+    const { handleSubmit } = useForm<
+      { test: string },
+      unknown,
+      { test: string } | { test1: number }
+    >();
+
+    handleSubmit((data) => {
+      // @ts-expect-error `data` should be union and thus should not be assignable to `{ test: string }`
+      expectType<{ test: string }>(data);
+      // @ts-expect-error `data` should be union and thus should not be assignable to `{ test1: number }`
+      expectType<{ test1: number }>(data);
+      expectType<{ test: string } | { test1: number }>(data);
+    });
+  }
 }
 
 /** {@link UseFormGetFieldState} */ {
diff --git a/src/logic/createFormControl.ts b/src/logic/createFormControl.ts
index d4436655c6f..7b8f823ebf0 100644
--- a/src/logic/createFormControl.ts
+++ b/src/logic/createFormControl.ts
@@ -93,10 +93,14 @@ const defaultOptions = {
 export function createFormControl<
   TFieldValues extends FieldValues = FieldValues,
   TContext = any,
+  TTransformedValues extends FieldValues = TFieldValues,
 >(
   props: UseFormProps<TFieldValues, TContext> = {},
   flushRootRender: () => void,
-): Omit<UseFormReturn<TFieldValues, TContext>, 'formState'> {
+): Omit<
+  UseFormReturn<TFieldValues, TContext, TTransformedValues>,
+  'formState'
+> {
   let _options = {
     ...defaultOptions,
     ...props,
@@ -1096,7 +1100,7 @@ export function createFormControl<
     }
   };
 
-  const handleSubmit: UseFormHandleSubmit<TFieldValues> =
+  const handleSubmit: UseFormHandleSubmit<TFieldValues, TTransformedValues> =
     (onValid, onInvalid) => async (e) => {
       let onValidError = undefined;
       if (e) {
@@ -1124,7 +1128,7 @@ export function createFormControl<
           errors: {},
         });
         try {
-          await onValid(fieldValues as TFieldValues, e);
+          await onValid(fieldValues as TFieldValues & TTransformedValues, e);
         } catch (error) {
           onValidError = error;
         }
diff --git a/src/logic/getProxyFormState.ts b/src/logic/getProxyFormState.ts
index 2c7402c6e71..07fa95ba6b1 100644
--- a/src/logic/getProxyFormState.ts
+++ b/src/logic/getProxyFormState.ts
@@ -1,9 +1,13 @@
 import { VALIDATION_MODE } from '../constants';
 import { Control, FieldValues, FormState, ReadFormState } from '../types';
 
-export default <TFieldValues extends FieldValues, TContext = any>(
+export default <
+  TFieldValues extends FieldValues,
+  TContext = any,
+  TTransformedValues extends FieldValues = TFieldValues,
+>(
   formState: FormState<TFieldValues>,
-  control: Control<TFieldValues, TContext>,
+  control: Control<TFieldValues, TContext, TTransformedValues>,
   localProxyFormState?: ReadFormState,
   isRoot = true,
 ) => {
diff --git a/src/types/form.ts b/src/types/form.ts
index 2f20133ed46..dfba04dbbc8 100644
--- a/src/types/form.ts
+++ b/src/types/form.ts
@@ -627,13 +627,9 @@ export type UseFormUnregister<TFieldValues extends FieldValues> = (
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 export type UseFormHandleSubmit<
   TFieldValues extends FieldValues,
-  TTransformedValues extends FieldValues | undefined = undefined,
+  TTransformedValues extends FieldValues = TFieldValues,
 > = (
-  onValid: TTransformedValues extends undefined
-    ? SubmitHandler<TFieldValues>
-    : TTransformedValues extends FieldValues
-    ? SubmitHandler<TTransformedValues>
-    : never,
+  onValid: SubmitHandler<TTransformedValues>,
   onInvalid?: SubmitErrorHandler<TFieldValues>,
 ) => (e?: React.BaseSyntheticEvent) => Promise<void>;
 
@@ -769,6 +765,7 @@ export type BatchFieldArrayUpdate = <
 export type Control<
   TFieldValues extends FieldValues = FieldValues,
   TContext = any,
+  TTransformedValues extends FieldValues = TFieldValues,
 > = {
   _subjects: Subjects<TFieldValues>;
   _removeUnmounted: Noop;
@@ -815,7 +812,7 @@ export type Control<
     names: InternalFieldName[],
   ) => Promise<{ errors: FieldErrors }>;
   register: UseFormRegister<TFieldValues>;
-  handleSubmit: UseFormHandleSubmit<TFieldValues>;
+  handleSubmit: UseFormHandleSubmit<TFieldValues, TTransformedValues>;
   _disableForm: (disabled?: boolean) => void;
   unregister: UseFormUnregister<TFieldValues>;
   getFieldState: UseFormGetFieldState<TFieldValues>;
@@ -833,7 +830,7 @@ export type WatchObserver<TFieldValues extends FieldValues> = (
 export type UseFormReturn<
   TFieldValues extends FieldValues = FieldValues,
   TContext = any,
-  TTransformedValues extends FieldValues | undefined = undefined,
+  TTransformedValues extends FieldValues = TFieldValues,
 > = {
   watch: UseFormWatch<TFieldValues>;
   getValues: UseFormGetValues<TFieldValues>;
@@ -847,7 +844,7 @@ export type UseFormReturn<
   reset: UseFormReset<TFieldValues>;
   handleSubmit: UseFormHandleSubmit<TFieldValues, TTransformedValues>;
   unregister: UseFormUnregister<TFieldValues>;
-  control: Control<TFieldValues, TContext>;
+  control: Control<TFieldValues, TContext, TTransformedValues>;
   register: UseFormRegister<TFieldValues>;
   setFocus: UseFormSetFocus<TFieldValues>;
 };
@@ -879,7 +876,7 @@ export type UseWatchProps<TFieldValues extends FieldValues = FieldValues> = {
 export type FormProviderProps<
   TFieldValues extends FieldValues = FieldValues,
   TContext = any,
-  TTransformedValues extends FieldValues | undefined = undefined,
+  TTransformedValues extends FieldValues = TFieldValues,
 > = {
   children: React.ReactNode | React.ReactNode[];
 } & UseFormReturn<TFieldValues, TContext, TTransformedValues>;
diff --git a/src/useForm.ts b/src/useForm.ts
index dc1733cd750..404f2b0cc34 100644
--- a/src/useForm.ts
+++ b/src/useForm.ts
@@ -46,7 +46,7 @@ import { useSubscribe } from './useSubscribe';
 export function useForm<
   TFieldValues extends FieldValues = FieldValues,
   TContext = any,
-  TTransformedValues extends FieldValues | undefined = undefined,
+  TTransformedValues extends FieldValues = TFieldValues,
 >(
   props: UseFormProps<TFieldValues, TContext> = {},
 ): UseFormReturn<TFieldValues, TContext, TTransformedValues> {
diff --git a/src/useFormContext.tsx b/src/useFormContext.tsx
index 5b54bd6b7b8..6ce43e690da 100644
--- a/src/useFormContext.tsx
+++ b/src/useFormContext.tsx
@@ -37,7 +37,7 @@ const HookFormContext = React.createContext<UseFormReturn | null>(null);
 export const useFormContext = <
   TFieldValues extends FieldValues,
   TContext = any,
-  TransformedValues extends FieldValues | undefined = undefined,
+  TransformedValues extends FieldValues = TFieldValues,
 >(): UseFormReturn<TFieldValues, TContext, TransformedValues> =>
   React.useContext(HookFormContext) as UseFormReturn<
     TFieldValues,
@@ -78,7 +78,7 @@ export const useFormContext = <
 export const FormProvider = <
   TFieldValues extends FieldValues,
   TContext = any,
-  TTransformedValues extends FieldValues | undefined = undefined,
+  TTransformedValues extends FieldValues = TFieldValues,
 >(
   props: FormProviderProps<TFieldValues, TContext, TTransformedValues>,
 ) => {