diff --git a/README.md b/README.md
index f28649f..22d27d6 100644
--- a/README.md
+++ b/README.md
@@ -224,7 +224,7 @@ All Result types (both Ok and Err) implement these methods:
 - `inspectErr(callable $fn): Result` - Calls a function with the error value if Err
 
 #### Pattern Matching
-- `match(callable $okFn, callable $errFn): mixed` - Pattern match on the Result
+- `match(callable $ok, callable $err): mixed` - Pattern match on the Result
 
 ## License
 
diff --git a/src/Err.php b/src/Err.php
index 968d589..6e08215 100644
--- a/src/Err.php
+++ b/src/Err.php
@@ -147,15 +147,15 @@ public function mapOr(mixed $default, callable $fn): mixed
      * @template U
      * @template V
      *
-     * @param callable(): U $default_fn
+     * @param callable(): U $defaultFn
      * @param callable(never): V $fn
      *
      * @return U
      */
     #[Override]
-    public function mapOrElse(callable $default_fn, callable $fn): mixed
+    public function mapOrElse(callable $defaultFn, callable $fn): mixed
     {
-        return $default_fn();
+        return $defaultFn();
     }
 
     /**
@@ -189,8 +189,8 @@ public function orElse(callable $fn): Result
     }
 
     #[Override]
-    public function match(callable $ok_fn, callable $err_fn): mixed
+    public function match(callable $ok, callable $err): mixed
     {
-        return $err_fn($this->value);
+        return $err($this->value);
     }
 }
diff --git a/src/Ok.php b/src/Ok.php
index fea4b7b..53565c0 100644
--- a/src/Ok.php
+++ b/src/Ok.php
@@ -146,13 +146,13 @@ public function mapOr(mixed $default, callable $fn): mixed
      * @template U
      * @template V
      *
-     * @param callable(): V $default_fn
+     * @param callable(): V $defaultFn
      * @param callable(T): U $fn
      *
      * @return U
      */
     #[Override]
-    public function mapOrElse(callable $default_fn, callable $fn): mixed
+    public function mapOrElse(callable $defaultFn, callable $fn): mixed
     {
         return $fn($this->value);
     }
@@ -188,8 +188,8 @@ public function orElse(callable $fn): Result
     }
 
     #[Override]
-    public function match(callable $ok_fn, callable $err_fn): mixed
+    public function match(callable $ok, callable $err): mixed
     {
-        return $ok_fn($this->value);
+        return $ok($this->value);
     }
 }
diff --git a/src/Result.php b/src/Result.php
index 67f2fd4..c2752cc 100644
--- a/src/Result.php
+++ b/src/Result.php
@@ -146,12 +146,12 @@ public function mapOr(mixed $default, callable $fn): mixed;
      *
      * @template U
      *
-     * @param callable(): U $default_fn
+     * @param callable(): U $defaultFn
      * @param callable(T): U $fn
      *
      * @return U
      */
-    public function mapOrElse(callable $default_fn, callable $fn): mixed;
+    public function mapOrElse(callable $defaultFn, callable $fn): mixed;
 
     /**
      * 成功の場合は第2の結果を返し、失敗の場合は最初のエラーを返します.
@@ -206,15 +206,15 @@ public function or(self $res): self;
     public function orElse(callable $fn): self;
 
     /**
-     * 成功の場合はok_fnを、失敗の場合はerr_fnを適用します.
+     * 成功の場合はokを、失敗の場合はerrを適用します.
      *
      * @template U
      * @template V
      *
-     * @param callable(T): U $ok_fn 成功値に適用する関数
-     * @param callable(E): V $err_fn エラー値に適用する関数
+     * @param callable(T): U $ok 成功値に適用する関数
+     * @param callable(E): V $err エラー値に適用する関数
      *
      * @return U|V 適用された関数の結果
      */
-    public function match(callable $ok_fn, callable $err_fn): mixed;
+    public function match(callable $ok, callable $err): mixed;
 }
diff --git a/tests/ErrTest.php b/tests/ErrTest.php
index 30b5aa9..e53ba0e 100644
--- a/tests/ErrTest.php
+++ b/tests/ErrTest.php
@@ -276,6 +276,25 @@ public function match_withDifferentReturnTypes_returns_err_branch(): void
         $this->assertSame(['status' => 'error', 'code' => 404], $result);
     }
 
+    #[Test]
+    public function match_supportsNamedArguments(): void
+    {
+        $err = new Err('error');
+        $result = $err->match(
+            ok: fn ($value) => "Success: $value",
+            err: fn ($error) => "Error: $error",
+        );
+        $this->assertSame('Error: error', $result);
+    }
+
+    #[Test]
+    public function mapOrElse_supportsNamedArguments(): void
+    {
+        $err = new Err('error');
+        $result = $err->mapOrElse(defaultFn: fn () => 100, fn: fn ($x) => $x * 2);
+        $this->assertSame(100, $result);
+    }
+
     #[Test]
     public function err_withNullValue_handles_null(): void
     {
diff --git a/tests/OkTest.php b/tests/OkTest.php
index 309282c..db780ab 100644
--- a/tests/OkTest.php
+++ b/tests/OkTest.php
@@ -267,6 +267,25 @@ public function match_withDifferentReturnTypes_returns_ok_branch(): void
         $this->assertSame(5, $result);
     }
 
+    #[Test]
+    public function match_supportsNamedArguments(): void
+    {
+        $ok = new Ok(42);
+        $result = $ok->match(
+            ok: fn ($value) => "Success: $value",
+            err: fn ($error) => "Error: $error",
+        );
+        $this->assertSame('Success: 42', $result);
+    }
+
+    #[Test]
+    public function mapOrElse_supportsNamedArguments(): void
+    {
+        $ok = new Ok(10);
+        $result = $ok->mapOrElse(defaultFn: fn () => 100, fn: fn ($x) => $x * 2);
+        $this->assertSame(20, $result);
+    }
+
     #[Test]
     public function ok_withNullValue_handles_null(): void
     {