diff --git a/src/Providers/Http/Exception/ServerException.php b/src/Providers/Http/Exception/ServerException.php
index b366c719..bc4b63de 100644
--- a/src/Providers/Http/Exception/ServerException.php
+++ b/src/Providers/Http/Exception/ServerException.php
@@ -38,6 +38,7 @@ public static function fromServerErrorResponse(Response $response): self
             503 => 'Service Unavailable',
             504 => 'Gateway Timeout',
             507 => 'Insufficient Storage',
+            529 => 'Overloaded',
         ];
 
         if (isset($statusTexts[$statusCode])) {
diff --git a/tests/unit/Exceptions/ExceptionsTest.php b/tests/unit/Exceptions/ExceptionsTest.php
index fe3b88b0..8dd5315c 100644
--- a/tests/unit/Exceptions/ExceptionsTest.php
+++ b/tests/unit/Exceptions/ExceptionsTest.php
@@ -9,8 +9,10 @@
 use WordPress\AiClient\Common\Exception\InvalidArgumentException;
 use WordPress\AiClient\Common\Exception\RuntimeException;
 use WordPress\AiClient\Common\Exception\TokenLimitReachedException;
+use WordPress\AiClient\Providers\Http\DTO\Response;
 use WordPress\AiClient\Providers\Http\Exception\ClientException;
 use WordPress\AiClient\Providers\Http\Exception\NetworkException;
+use WordPress\AiClient\Providers\Http\Exception\ServerException;
 
 /**
  * Tests for AI Client exceptions.
@@ -21,6 +23,7 @@
  * @covers \WordPress\AiClient\Common\Exception\TokenLimitReachedException
  * @covers \WordPress\AiClient\Providers\Http\Exception\NetworkException
  * @covers \WordPress\AiClient\Providers\Http\Exception\ClientException
+ * @covers \WordPress\AiClient\Providers\Http\Exception\ServerException
  */
 class ExceptionsTest extends TestCase
 {
@@ -32,6 +35,7 @@ public function testAllExceptionsImplementAiClientExceptionInterface(): void
             new TokenLimitReachedException('test'),
             new NetworkException('test'),
             new ClientException('test'),
+            new ServerException('test'),
         ];
 
         foreach ($exceptions as $exception) {
@@ -68,6 +72,7 @@ public function testCatchAllFunctionality(): void
             new TokenLimitReachedException('token limit error'),
             new NetworkException('network error'),
             new ClientException('client error'),
+            new ServerException('server error'),
         ];
 
         foreach ($exceptions as $exception) {
@@ -81,4 +86,102 @@ public function testCatchAllFunctionality(): void
             $this->assertTrue($caught, 'Exception should be catchable as AiClientExceptionInterface');
         }
     }
+
+    public function testServerExceptionExtendsRuntimeException(): void
+    {
+        $exception = new ServerException('server error');
+
+        $this->assertInstanceOf(RuntimeException::class, $exception);
+    }
+
+    /**
+     * @dataProvider knownServerStatusCodeProvider
+     */
+    public function testServerExceptionFromKnownStatusCodes(int $statusCode, string $expectedText): void
+    {
+        $response = new Response($statusCode, []);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertSame($statusCode, $exception->getCode());
+        $this->assertStringContainsString($expectedText, $exception->getMessage());
+        $this->assertStringContainsString((string) $statusCode, $exception->getMessage());
+    }
+
+    /**
+     * @return array<string, array{int, string}>
+     */
+    public static function knownServerStatusCodeProvider(): array
+    {
+        return [
+            '500 Internal Server Error' => [500, 'Internal Server Error'],
+            '502 Bad Gateway'           => [502, 'Bad Gateway'],
+            '503 Service Unavailable'   => [503, 'Service Unavailable'],
+            '504 Gateway Timeout'       => [504, 'Gateway Timeout'],
+            '507 Insufficient Storage'  => [507, 'Insufficient Storage'],
+            '529 Overloaded'            => [529, 'Overloaded'],
+        ];
+    }
+
+    public function testServerExceptionFromUnknownStatusCode(): void
+    {
+        $response = new Response(599, []);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertSame(599, $exception->getCode());
+        $this->assertStringContainsString('Server error (599)', $exception->getMessage());
+        $this->assertStringContainsString('server-side issue', $exception->getMessage());
+    }
+
+    public function testServerExceptionExtractsErrorMessageFromResponseBody(): void
+    {
+        $body = json_encode(['error' => ['message' => 'The server is overloaded']]);
+        $response = new Response(500, [], $body);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertStringContainsString('Internal Server Error (500)', $exception->getMessage());
+        $this->assertStringContainsString('The server is overloaded', $exception->getMessage());
+    }
+
+    public function testServerExceptionExtractsStringErrorFromResponseBody(): void
+    {
+        $body = json_encode(['error' => 'Something went wrong']);
+        $response = new Response(502, [], $body);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertStringContainsString('Bad Gateway (502)', $exception->getMessage());
+        $this->assertStringContainsString('Something went wrong', $exception->getMessage());
+    }
+
+    public function testServerExceptionExtractsMessageKeyFromResponseBody(): void
+    {
+        $body = json_encode(['message' => 'Service temporarily unavailable']);
+        $response = new Response(503, [], $body);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertStringContainsString('Service Unavailable (503)', $exception->getMessage());
+        $this->assertStringContainsString('Service temporarily unavailable', $exception->getMessage());
+    }
+
+    public function testServerExceptionWithNoBody(): void
+    {
+        $response = new Response(500, []);
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertSame('Internal Server Error (500)', $exception->getMessage());
+    }
+
+    public function testServerExceptionWithNonJsonBody(): void
+    {
+        $response = new Response(500, [], '<html>Server Error</html>');
+
+        $exception = ServerException::fromServerErrorResponse($response);
+
+        $this->assertSame('Internal Server Error (500)', $exception->getMessage());
+    }
 }