diff --git a/src/DependencyInjection/CompilerPass/ProxyServiceWithMockPass.php b/src/DependencyInjection/CompilerPass/ProxyServiceWithMockPass.php
index 62bfad1..c69439c 100644
--- a/src/DependencyInjection/CompilerPass/ProxyServiceWithMockPass.php
+++ b/src/DependencyInjection/CompilerPass/ProxyServiceWithMockPass.php
@@ -42,9 +42,17 @@ public function process(ContainerBuilder $container)
             };
 
             $proxy = $factory->createProxy($definition->getClass(), $initializer);
-            $definition->setClass(get_class($proxy));
+            $definition->setClass($proxyClass = get_class($proxy));
             $definition->setPublic(true);
             $definition->setLazy(true);
+
+            if (null !== $definition->getFactory()) {
+                $factoryMethod = $definition->getFactory();
+                $arguments = $definition->getArguments();
+                array_unshift($arguments, $factoryMethod);
+                $definition->setFactory([$proxyClass, '__construct_with_factory']);
+                $definition->setArguments($arguments);
+            }
         }
     }
 }
diff --git a/src/Generator/LazyLoadingValueHolderGenerator.php b/src/Generator/LazyLoadingValueHolderGenerator.php
index 9381fd2..bfa081a 100644
--- a/src/Generator/LazyLoadingValueHolderGenerator.php
+++ b/src/Generator/LazyLoadingValueHolderGenerator.php
@@ -104,6 +104,7 @@ static function (MethodGenerator $generatedMethod) use ($originalClass, $classGe
                 [
                     new StaticProxyConstructor($initializer, Properties::fromReflectionClass($originalClass)),
                     Constructor::generateMethod($originalClass, $valueHolder), // Not a standard constructor
+                    StaticConstructor::generateMethod($valueHolder), // Not a standard constructor
                     new MagicGet($originalClass, $initializer, $valueHolder, $publicProperties),
                     new MagicSet($originalClass, $initializer, $valueHolder, $publicProperties),
                     new MagicIsset($originalClass, $initializer, $valueHolder, $publicProperties),
diff --git a/src/Generator/StaticConstructor.php b/src/Generator/StaticConstructor.php
new file mode 100644
index 0000000..825a2e4
--- /dev/null
+++ b/src/Generator/StaticConstructor.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Happyr\ServiceMocking\Generator;
+
+use Laminas\Code\Generator\Exception\InvalidArgumentException;
+use Laminas\Code\Generator\ParameterGenerator;
+use Laminas\Code\Generator\PropertyGenerator;
+use ProxyManager\Generator\MethodGenerator;
+
+/**
+ * The `__construct_with_factory` implementation for lazy loading proxies. This
+ * is used for services created with service factories.
+ *
+ * @interal
+ */
+class StaticConstructor extends MethodGenerator
+{
+    /**
+     * @throws InvalidArgumentException
+     */
+    public static function generateMethod(PropertyGenerator $valueHolder): self
+    {
+        $constructor = new self('__construct_with_factory');
+        $constructor->setStatic(true);
+        $constructor->setParameter(new ParameterGenerator('factory', 'callable'));
+        $parameter = new ParameterGenerator('arguments');
+        $parameter->setVariadic(true);
+        $constructor->setParameter($parameter);
+
+        $constructor->setBody(
+            'static $reflection;'."\n\n"
+            .'$reflection = $reflection ?? new \ReflectionClass(self::class);'."\n"
+            .'$model = $reflection->newInstanceWithoutConstructor();'."\n"
+            .'$model->'.$valueHolder->getName().' = \Closure::fromCallable($factory)->__invoke(...$arguments);'."\n"
+            .'\Happyr\ServiceMocking\ServiceMock::initializeProxy($model);'."\n\n"
+            .'return $model;'
+        );
+
+        return $constructor;
+    }
+}
diff --git a/tests/Functional/BundleInitializationTest.php b/tests/Functional/BundleInitializationTest.php
index 86219b3..3b9d5cd 100644
--- a/tests/Functional/BundleInitializationTest.php
+++ b/tests/Functional/BundleInitializationTest.php
@@ -7,6 +7,7 @@
 use Happyr\ServiceMocking\HappyrServiceMockingBundle;
 use Happyr\ServiceMocking\ServiceMock;
 use Happyr\ServiceMocking\Tests\Resource\ExampleService;
+use Happyr\ServiceMocking\Tests\Resource\ServiceWithFactory;
 use Happyr\ServiceMocking\Tests\Resource\StatefulService;
 use Nyholm\BundleTest\BaseBundleTestCase;
 use ProxyManager\Proxy\VirtualProxyInterface;
@@ -54,6 +55,21 @@ public function testInitBundle()
         ServiceMock::swap($service, $mock);
 
         $this->assertSame(2, $service->getNumber());
+
+        $serviceWithFactory = $container->get(ServiceWithFactory::class);
+        $this->assertSame(3, $serviceWithFactory->getSecretNumber());
+
+        $called = false;
+        ServiceMock::next($serviceWithFactory, 'getNumber', function ($dir) use (&$called) {
+            $called = true;
+            $this->assertSame(11, $dir);
+
+            return 17;
+        });
+
+        $this->assertSame(17, $serviceWithFactory->getNumber(11));
+        $this->assertTrue($called);
+        $this->assertSame(14, $serviceWithFactory->getNumber(11));
     }
 
     public function testRebootBundle()
diff --git a/tests/Functional/config.yml b/tests/Functional/config.yml
index 9433afc..86edf14 100644
--- a/tests/Functional/config.yml
+++ b/tests/Functional/config.yml
@@ -1,6 +1,7 @@
 happyr_service_mocking:
     services:
         - 'Happyr\ServiceMocking\Tests\Resource\ExampleService'
+        - 'Happyr\ServiceMocking\Tests\Resource\ServiceWithFactory'
 
 services:
 
@@ -10,3 +11,7 @@ services:
     Happyr\ServiceMocking\Tests\Resource\StatefulService:
         tags:
             - { name: happyr_service_mock }
+
+    Happyr\ServiceMocking\Tests\Resource\ServiceWithFactory:
+        factory: [Happyr\ServiceMocking\Tests\Resource\ServiceWithFactory, create]
+        arguments: [6,3]
diff --git a/tests/Resource/ServiceWithFactory.php b/tests/Resource/ServiceWithFactory.php
new file mode 100644
index 0000000..913a0b2
--- /dev/null
+++ b/tests/Resource/ServiceWithFactory.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Happyr\ServiceMocking\Tests\Resource;
+
+class ServiceWithFactory
+{
+    private $number;
+    private $secretNumber;
+
+    public function __construct(int $number)
+    {
+        $this->number = $number;
+    }
+
+    public static function create(int $number, int $secret)
+    {
+        $self = new self($number);
+        $self->secretNumber = $secret;
+
+        return $self;
+    }
+
+    public function getNumber(int $input = 0): int
+    {
+        return $this->number + $input - $this->secretNumber;
+    }
+
+    public function getSecretNumber(): int
+    {
+        return $this->secretNumber;
+    }
+}
diff --git a/tests/Unit/.gitignore b/tests/Unit/.gitignore
deleted file mode 100644
index e69de29..0000000