diff --git a/docs/ja/reference/function/partial.md b/docs/ja/reference/function/partial.md
index cca2c17e4..83d344044 100644
--- a/docs/ja/reference/function/partial.md
+++ b/docs/ja/reference/function/partial.md
@@ -11,7 +11,7 @@ Symbol型の`partial.placeholder`を使用すると、前もって提供した
 ## インターフェース
 
 ```typescript
-function partial<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): F;
+function partial<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partial {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partial {
 
 ### 戻り値
 
-(`F`): 前もって引数が提供された関数。
+(`(...args: any[]) => ReturnType<F>`): 前もって引数が提供された関数。
 
 ## 例
 
diff --git a/docs/ja/reference/function/partialRight.md b/docs/ja/reference/function/partialRight.md
index f545c7135..9891cc3b7 100644
--- a/docs/ja/reference/function/partialRight.md
+++ b/docs/ja/reference/function/partialRight.md
@@ -11,7 +11,7 @@ Symbol型の`partialRight.placeholder`を使用すると、事前に提供した
 ## インターフェース
 
 ```typescript
-function partialRight<F extends (...args: any[] => any)>(func: F, ...partialArgs: any[]): F;
+function partialRight<F extends (...args: any[] => any)>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partialRight {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partialRight {
 
 ### 戻り値
 
-(`F`): 事前に引数が提供された関数。
+(`(...args: any[]) => ReturnType<F>`): 事前に引数が提供された関数。
 
 ## 例
 
diff --git a/docs/ko/reference/function/partial.md b/docs/ko/reference/function/partial.md
index ff153b08d..614e9ee51 100644
--- a/docs/ko/reference/function/partial.md
+++ b/docs/ko/reference/function/partial.md
@@ -11,7 +11,7 @@ Symbol 타입의 `partial.placeholder`를 쓰면, 미리 제공한 인자가 사
 ## 인터페이스
 
 ```typescript
-function partial<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): F;
+function partial<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partial {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partial {
 
 ### 반환 값
 
-(`F`): 미리 인자가 제공된 함수.
+(`(...args: any[]) => ReturnType<F>`): 미리 인자가 제공된 함수.
 
 ## 예시
 
diff --git a/docs/ko/reference/function/partialRight.md b/docs/ko/reference/function/partialRight.md
index 2a756e927..6a463caa2 100644
--- a/docs/ko/reference/function/partialRight.md
+++ b/docs/ko/reference/function/partialRight.md
@@ -11,7 +11,7 @@ Symbol 타입의 `partialRight.placeholder`를 쓰면, 미리 제공한 인자
 ## 인터페이스
 
 ```typescript
-function partialRight<F extends (...args: any[] => any)>(func: F, ...partialArgs: any[]): F;
+function partialRight<F extends (...args: any[] => any)>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partialRight {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partialRight {
 
 ### 반환 값
 
-(`F`): 미리 인자가 제공된 함수.
+(`(...args: any[]) => ReturnType<F>`): 미리 인자가 제공된 함수.
 
 ## 예시
 
diff --git a/docs/reference/function/partial.md b/docs/reference/function/partial.md
index 7d0fbeb8e..f7e212521 100644
--- a/docs/reference/function/partial.md
+++ b/docs/reference/function/partial.md
@@ -11,7 +11,7 @@ Note: This method doesn't set the `length` property of partially applied functio
 ## Signature
 
 ```typescript
-function partial<F extends Function>(func: F, ...partialArgs: any[]): F;
+function partial<F extends Function>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partial {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partial {
 
 ### Returns
 
-(`F`): Returns the new partially applied function.
+(`(...args: any[]) => ReturnType<F>`): Returns the new partially applied function.
 
 ## Examples
 
diff --git a/docs/reference/function/partialRight.md b/docs/reference/function/partialRight.md
index 28320365b..47d8bfcd7 100644
--- a/docs/reference/function/partialRight.md
+++ b/docs/reference/function/partialRight.md
@@ -11,7 +11,7 @@ Note: This method doesn't set the `length` property of partially applied functio
 ## Signature
 
 ```typescript
-function partialRight<F extends Function>(func: F, ...partialArgs: any[]): F;
+function partialRight<F extends Function>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partialRight {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partialRight {
 
 ### Returns
 
-(`F`): Returns the new partially applied function.
+(`(...args: any[]) => ReturnType<F>`): Returns the new partially applied function.
 
 ## Examples
 
diff --git a/docs/zh_hans/reference/function/partial.md b/docs/zh_hans/reference/function/partial.md
index 8a2324ad1..70fcb710d 100644
--- a/docs/zh_hans/reference/function/partial.md
+++ b/docs/zh_hans/reference/function/partial.md
@@ -11,7 +11,7 @@
 ## 签名
 
 ```typescript
-function partial<F extends Function>(func: F, ...partialArgs: any[]): F;
+function partial<F extends Function>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partial {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partial {
 
 ### 返回值
 
-(`F`): 返回新的部分应用函数。
+(`(...args: any[]) => ReturnType<F>`): 返回新的部分应用函数。
 
 ## 示例
 
diff --git a/docs/zh_hans/reference/function/partialRight.md b/docs/zh_hans/reference/function/partialRight.md
index 6f821b0ce..f2261b43f 100644
--- a/docs/zh_hans/reference/function/partialRight.md
+++ b/docs/zh_hans/reference/function/partialRight.md
@@ -11,7 +11,7 @@
 ## 签名
 
 ```typescript
-function partialRight<F extends Function>(func: F, ...partialArgs: any[]): F;
+function partialRight<F extends Function>(func: F, ...partialArgs: any[]): (...args: any[]) => ReturnType<F>;
 
 namespace partialRight {
   placeholder: symbol;
@@ -25,7 +25,7 @@ namespace partialRight {
 
 ### 返回值
 
-(`F`): 返回新的部分应用函数。
+(`(...args: any[]) => ReturnType<F>`): 返回新的部分应用函数。
 
 ## 示例
 
diff --git a/src/compat/util/iteratee.spec.ts b/src/compat/util/iteratee.spec.ts
index 3feb47f1f..61e794de5 100644
--- a/src/compat/util/iteratee.spec.ts
+++ b/src/compat/util/iteratee.spec.ts
@@ -133,13 +133,9 @@ describe('iteratee', () => {
     const expected = [1, 2, 3];
     const object = { a: 1, iteratee: iteratee(partial(fn, 2)) };
 
-    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-    // @ts-expect-error
     expect(object.iteratee(3)).toEqual(expected);
 
     object.iteratee = iteratee(partialRight(fn, 3));
-    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-    // @ts-expect-error
     expect(object.iteratee(2)).toEqual(expected);
   });
 
diff --git a/src/function/partial.spec.ts b/src/function/partial.spec.ts
index 49ddd8c27..246a5f5f4 100644
--- a/src/function/partial.spec.ts
+++ b/src/function/partial.spec.ts
@@ -14,7 +14,7 @@ describe('partial', () => {
   });
 
   it('partial creates a function that can be invoked with additional arguments', () => {
-    const fn = function (a?: string, b?: string) {
+    const fn = function (a: string, b: string) {
       return [a, b];
     };
     const par = partial(fn, 'a');
@@ -70,7 +70,7 @@ describe('partial', () => {
   });
 
   it('partial clones metadata for created functions', () => {
-    function greet(greeting?: string, name?: string) {
+    function greet(greeting: string, name: string) {
       return `${greeting} ${name}`;
     }
 
diff --git a/src/function/partial.ts b/src/function/partial.ts
index fe3ad0c65..22bc1b1bd 100644
--- a/src/function/partial.ts
+++ b/src/function/partial.ts
@@ -8,7 +8,7 @@
  * @template F The type of the function to partially apply.
  * @param {F} func The function to partially apply arguments to.
  * @param {any[]} partialArgs The arguments to be partially applied.
- * @returns {F} Returns the new partially applied function.
+ * @returns {(...args: any[]) => ReturnType<F>} Returns the new partially applied function.
  *
  * @example
  * function greet(greeting, name) {
@@ -24,7 +24,10 @@
  * greetFred('hi');
  * // => 'hi fred'
  */
-export function partial<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): F {
+export function partial<F extends (...args: any[]) => any>(
+  func: F,
+  ...partialArgs: any[]
+): (...args: any[]) => ReturnType<F> {
   return function (this: any, ...providedArgs: any[]) {
     const args: any[] = [];
 
diff --git a/src/function/partialRight.spec.ts b/src/function/partialRight.spec.ts
index 55170f922..ec0555881 100644
--- a/src/function/partialRight.spec.ts
+++ b/src/function/partialRight.spec.ts
@@ -14,7 +14,7 @@ describe('partialRight', () => {
   });
 
   it('partialRight creates a function that can be invoked with additional arguments', () => {
-    const fn = function (a?: string, b?: string) {
+    const fn = function (a: string, b: string) {
       return [a, b];
     };
     const par = partialRight(fn, 'a');
@@ -71,7 +71,7 @@ describe('partialRight', () => {
   });
 
   it('partialRight clones metadata for created functions', () => {
-    function greet(greeting?: string, name?: string) {
+    function greet(greeting: string, name: string) {
       return `${greeting} ${name}`;
     }
 
diff --git a/src/function/partialRight.ts b/src/function/partialRight.ts
index f96e06ead..20007283b 100644
--- a/src/function/partialRight.ts
+++ b/src/function/partialRight.ts
@@ -8,7 +8,7 @@
  * @template F The type of the function to partially apply.
  * @param {F} func The function to partially apply arguments to.
  * @param {any[]} partialArgs The arguments to be partially applied.
- * @returns {F} Returns the new partially applied function.
+ * @returns {(...args: any[]) => ReturnType<F>} Returns the new partially applied function.
  *
  * @example
  * function greet(greeting, name) {
@@ -24,7 +24,10 @@
  * sayHelloTo('fred');
  * // => 'hello fred'
  */
-export function partialRight<F extends (...args: any[]) => any>(func: F, ...partialArgs: any[]): F {
+export function partialRight<F extends (...args: any[]) => any>(
+  func: F,
+  ...partialArgs: any[]
+): (...args: any[]) => ReturnType<F> {
   return function (this: any, ...providedArgs: any[]) {
     const placeholderLength = partialArgs.filter(arg => arg === partialRightPlaceholder).length;
     const rangeLength = Math.max(providedArgs.length - placeholderLength, 0);