diff --git a/src/AsyncClient.php b/src/AsyncClient.php
new file mode 100644
index 00000000..70aa23aa
--- /dev/null
+++ b/src/AsyncClient.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types=1);
+
+namespace Spawnia\Sailor;
+
+
+interface AsyncClient extends Client
+{
+    /** Execute a GraphQL query against an endpoint and return a Response. */
+    public function requestAsync(string $query, \stdClass $variables = null);
+}
diff --git a/src/Client/Guzzle.php b/src/Client/Guzzle.php
index 7eb720e8..2ecc77cf 100644
--- a/src/Client/Guzzle.php
+++ b/src/Client/Guzzle.php
@@ -3,10 +3,12 @@
 namespace Spawnia\Sailor\Client;
 
 use GuzzleHttp\Client as GuzzleClient;
-use Spawnia\Sailor\Client;
+use GuzzleHttp\Promise\PromiseInterface;
+use Psr\Http\Message\ResponseInterface;
+use Spawnia\Sailor\AsyncClient;
 use Spawnia\Sailor\Response;
 
-class Guzzle implements Client
+class Guzzle implements AsyncClient
 {
     protected string $uri;
 
@@ -30,4 +32,20 @@ public function request(string $query, \stdClass $variables = null): Response
 
         return Response::fromResponseInterface($response);
     }
+
+    public function requestAsync(string $query, \stdClass $variables = null): PromiseInterface
+    {
+        $json = ['query' => $query];
+        if (! is_null($variables)) {
+            $json['variables'] = $variables;
+        }
+
+        $promise = $this->guzzle->postAsync($this->uri, ['json' => $json]);
+
+        return $promise->then(
+            function (ResponseInterface $response) {
+                return Response::fromResponseInterface($response);
+            }
+        );
+    }
 }
diff --git a/src/Codegen/OperationBuilder.php b/src/Codegen/OperationBuilder.php
index faa63798..3609fe2f 100644
--- a/src/Codegen/OperationBuilder.php
+++ b/src/Codegen/OperationBuilder.php
@@ -19,6 +19,8 @@ class OperationBuilder
 
     private Method $execute;
 
+    private Method $executeAsync;
+
     private Method $converters;
 
     /** @var array<PropertyArgs> */
@@ -40,6 +42,11 @@ public function __construct(string $name, string $namespace)
         $execute->addBody('return self::executeOperation(');
         $this->execute = $execute;
 
+        $executeAsync = $class->addMethod('executeAsync');
+        $executeAsync->setStatic(true);
+        $executeAsync->addBody('return self::executeOperationAsync(');
+        $this->executeAsync = $executeAsync;
+
         $converters = $class->addMethod('converters');
         $converters->setStatic(true);
         $converters->setProtected();
@@ -101,6 +108,7 @@ public function build(): ClassType
 
         $this->converters->addBody(/** @lang PHP */ '];');
         $this->execute->addBody(');');
+        $this->executeAsync->addBody(');');
 
         return $this->class;
     }
@@ -120,6 +128,7 @@ protected function buildVariable(string $name, Type $type, string $typeReference
         $this->converters->addBody(/** @lang PHP */ "    ['{$name}', {$wrappedTypeConverter}],");
 
         $this->execute->addComment(/** @lang PHPDoc */ "@param {$wrappedPhpDocType} \${$name}");
+        $this->executeAsync->addComment(/** @lang PHPDoc */ "@param {$wrappedPhpDocType} \${$name}");
 
         // TODO support default values properly
         $parameter = $this->execute->addParameter($name);
@@ -128,6 +137,13 @@ protected function buildVariable(string $name, Type $type, string $typeReference
             $parameter->setDefaultValue(ObjectLike::UNDEFINED);
         }
 
+        $parameterAsync = $this->executeAsync->addParameter($name);
+        if (! $type instanceof NonNull || $defaultValue !== null) {
+            $parameterAsync->setNullable(true);
+            $parameterAsync->setDefaultValue(ObjectLike::UNDEFINED);
+        }
+
         $this->execute->addBody(/** @lang PHP */ "    \${$name},");
+        $this->executeAsync->addBody(/** @lang PHP */ "    \${$name},");
     }
 }
diff --git a/src/Operation.php b/src/Operation.php
index 4ccce203..2879cb70 100644
--- a/src/Operation.php
+++ b/src/Operation.php
@@ -87,6 +87,64 @@ protected static function fetchResponse(array $args): Response
         return $response;
     }
 
+
+    /**
+     * @param  mixed  ...$args type depends on the subclass
+     *
+     * @return \GuzzleHttp\Promise\PromiseInterface
+     */
+    protected static function executeOperationAsync(...$args)
+    {
+        $mock = self::$mocks[static::class] ?? null;
+        if ($mock !== null) {
+            // @phpstan-ignore-next-line This function is only present on child classes
+            return $mock::executeAsync(...$args);
+        }
+
+        return self::fetchResponseAsync($args)->then(
+            function ($response) {
+                $child = static::class;
+                $parts = explode('\\', $child);
+                $basename = end($parts);
+
+                $resultClass = $child . '\\' . $basename . 'Result';
+                assert(class_exists($resultClass));
+
+                return $resultClass::fromResponse($response);
+            }
+        );
+    }
+
+    /**
+     * Send an operation through the client and return the response.
+     *
+     * @param  array<int, mixed>  $args
+     */
+    protected static function fetchResponseAsync(array $args)
+    {
+        $endpointConfig = Configuration::endpoint(static::config(), static::endpoint());
+
+        $document = static::document();
+        $variables = static::variables($args);
+
+        $endpointConfig->handleEvent(new StartRequest($document, $variables));
+
+        $client = self::$clients[static::class] ??= $endpointConfig->makeClient();
+        if (! $client instanceof AsyncClient) {
+            throw new \InvalidArgumentException('Please provide an async client in order to perform async requests.');
+        }
+
+        $promise = $client->requestAsync($document, $variables);
+
+        return $promise->then(
+            function (Response $response) use ($endpointConfig) {
+                $endpointConfig->handleEvent(new ReceiveResponse($response));
+                return $response;
+            }
+        );
+    }
+
+
     /** @param array<int, mixed> $args */
     protected static function variables(array $args): \stdClass
     {
diff --git a/src/Testing/MockClient.php b/src/Testing/MockClient.php
index c4ae5cfd..13a60dcc 100644
--- a/src/Testing/MockClient.php
+++ b/src/Testing/MockClient.php
@@ -2,13 +2,14 @@
 
 namespace Spawnia\Sailor\Testing;
 
-use Spawnia\Sailor\Client;
+use GuzzleHttp\Promise\Promise;
+use Spawnia\Sailor\AsyncClient;
 use Spawnia\Sailor\Response;
 
 /**
  * @phpstan-type Request callable(string, \stdClass|null): Response
  */
-class MockClient implements Client
+class MockClient implements AsyncClient
 {
     /** @var Request */
     private $request;
@@ -28,4 +29,15 @@ public function request(string $query, \stdClass $variables = null): Response
 
         return ($this->request)($query, $variables);
     }
+
+    public function requestAsync(string $query, ?\stdClass $variables = null): Promise
+    {
+        $this->storedRequests[] = new MockRequest($query, $variables);
+        $promise = new Promise(function () use (&$promise, $query, $variables) {
+            $response = ($this->request)($query, $variables);
+            /** @var Promise $promise */
+            $promise->resolve($response);
+        });
+        return $promise;
+    }
 }
diff --git a/tests/Unit/Client/GuzzleTest.php b/tests/Unit/Client/GuzzleTest.php
index eb269539..ea7344bc 100644
--- a/tests/Unit/Client/GuzzleTest.php
+++ b/tests/Unit/Client/GuzzleTest.php
@@ -39,4 +39,34 @@ public function testRequest(): void
         self::assertSame(/* @lang JSON */ '{"query":"{simple}"}', $request->getBody()->getContents());
         self::assertSame($uri, $request->getUri()->__toString());
     }
+
+    public function testAsyncRequest(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+
+        $mock = new MockHandler([
+            new Response(200, [], /* @lang JSON */ '{"data": {"simple": "bar"}}'),
+        ]);
+        $stack = HandlerStack::create($mock);
+        $stack->push($history);
+
+        $uri = 'https://simple.bar/graphql';
+        $client = new Guzzle($uri, ['handler' => $stack]);
+        $promise = $client->requestAsync(/* @lang GraphQL */ '{simple}');
+
+        $response = $promise->wait();
+
+        self::assertEquals(
+            (object) ['simple' => 'bar'],
+            $response->data
+        );
+
+        $request = $container[0]['request'];
+        assert($request instanceof Request);
+
+        self::assertSame('POST', $request->getMethod());
+        self::assertSame(/* @lang JSON */ '{"query":"{simple}"}', $request->getBody()->getContents());
+        self::assertSame($uri, $request->getUri()->__toString());
+    }
 }
diff --git a/tests/Unit/Testing/MockClientTest.php b/tests/Unit/Testing/MockClientTest.php
index 2417baa4..81cc7b43 100644
--- a/tests/Unit/Testing/MockClientTest.php
+++ b/tests/Unit/Testing/MockClientTest.php
@@ -16,7 +16,7 @@ public function testCallsMock(): void
         $response = new Response();
 
         $responseMock = self::createPartialMock(Invokable::class, ['__invoke']);
-        $responseMock->expects(self::once())
+        $responseMock->expects(self::exactly(2))
             ->method('__invoke')
             ->with($query, $variables)
             ->willReturn($response);
@@ -29,5 +29,12 @@ public function testCallsMock(): void
 
         self::assertSame($query, $storedRequest->query);
         self::assertSame($variables, $storedRequest->variables);
+
+        $mockClient->requestAsync($query, $variables)->wait();
+
+        $storedRequest = $mockClient->storedRequests[1];
+
+        self::assertSame($query, $storedRequest->query);
+        self::assertSame($variables, $storedRequest->variables);
     }
 }