diff --git a/extension.neon b/extension.neon
index af69d8bf..531eb7df 100644
--- a/extension.neon
+++ b/extension.neon
@@ -14,6 +14,9 @@ parameters:
 	featureToggles:
 		skipCheckGenericClasses:
 			- Symfony\Component\Form\AbstractType
+			- Symfony\Component\Form\FormBuilderInterface
+			- Symfony\Component\Form\FormConfigBuilderInterface
+			- Symfony\Component\Form\FormConfigInterface
 			- Symfony\Component\Form\FormInterface
 			- Symfony\Component\Form\FormTypeExtensionInterface
 			- Symfony\Component\Form\FormTypeInterface
@@ -47,6 +50,8 @@ parameters:
 		- stubs/Symfony/Component/Form/Exception/TransformationFailedException.stub
 		- stubs/Symfony/Component/Form/DataTransformerInterface.stub
 		- stubs/Symfony/Component/Form/FormBuilderInterface.stub
+		- stubs/Symfony/Component/Form/FormConfigBuilderInterface.stub
+		- stubs/Symfony/Component/Form/FormConfigInterface.stub
 		- stubs/Symfony/Component/Form/FormInterface.stub
 		- stubs/Symfony/Component/Form/FormFactoryInterface.stub
 		- stubs/Symfony/Component/Form/FormTypeExtensionInterface.stub
@@ -341,3 +346,8 @@ services:
 	-
 		factory: PHPStan\Type\Symfony\CacheInterfaceGetDynamicReturnTypeExtension
 		tags: [phpstan.broker.dynamicMethodReturnTypeExtension]
+
+	# Extension::getConfiguration() return type
+	-
+		factory: PHPStan\Type\Symfony\ExtensionGetConfigurationReturnTypeExtension
+		tags: [phpstan.broker.dynamicMethodReturnTypeExtension]
diff --git a/src/Type/Symfony/ExtensionGetConfigurationReturnTypeExtension.php b/src/Type/Symfony/ExtensionGetConfigurationReturnTypeExtension.php
new file mode 100644
index 00000000..7af50773
--- /dev/null
+++ b/src/Type/Symfony/ExtensionGetConfigurationReturnTypeExtension.php
@@ -0,0 +1,105 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Symfony;
+
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\ClassReflection;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\NullType;
+use PHPStan\Type\ObjectType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use function str_contains;
+use function strrpos;
+use function substr_replace;
+
+class ExtensionGetConfigurationReturnTypeExtension implements DynamicMethodReturnTypeExtension
+{
+
+	/** @var ReflectionProvider */
+	private $reflectionProvider;
+
+	public function __construct(ReflectionProvider $reflectionProvider)
+	{
+		$this->reflectionProvider = $reflectionProvider;
+	}
+
+	public function getClass(): string
+	{
+		return 'Symfony\Component\DependencyInjection\Extension\Extension';
+	}
+
+	public function isMethodSupported(MethodReflection $methodReflection): bool
+	{
+		return $methodReflection->getName() === 'getConfiguration'
+			&& $methodReflection->getDeclaringClass()->getName() === 'Symfony\Component\DependencyInjection\Extension\Extension';
+	}
+
+	public function getTypeFromMethodCall(
+		MethodReflection $methodReflection,
+		MethodCall $methodCall,
+		Scope $scope
+	): ?Type
+	{
+		$types = [];
+		$extensionType = $scope->getType($methodCall->var);
+		$classes = $extensionType->getObjectClassNames();
+
+		foreach ($classes as $extensionName) {
+			if (str_contains($extensionName, "\0")) {
+				$types[] = new NullType();
+				continue;
+			}
+
+			$lastBackslash = strrpos($extensionName, '\\');
+			if ($lastBackslash === false) {
+				$types[] = new NullType();
+				continue;
+			}
+
+			$configurationName = substr_replace($extensionName, '\Configuration', $lastBackslash);
+			if (!$this->reflectionProvider->hasClass($configurationName)) {
+				$types[] = new NullType();
+				continue;
+			}
+
+			$reflection = $this->reflectionProvider->getClass($configurationName);
+			if ($this->hasRequiredConstructor($reflection)) {
+				$types[] = new NullType();
+				continue;
+			}
+
+			$types[] = new ObjectType($configurationName);
+		}
+
+		return TypeCombinator::union(...$types);
+	}
+
+	private function hasRequiredConstructor(ClassReflection $class): bool
+	{
+		if (!$class->hasConstructor()) {
+			return false;
+		}
+
+		$constructor = $class->getConstructor();
+		foreach ($constructor->getVariants() as $variant) {
+			$anyRequired = false;
+			foreach ($variant->getParameters() as $parameter) {
+				if (!$parameter->isOptional()) {
+					$anyRequired = true;
+					break;
+				}
+			}
+
+			if (!$anyRequired) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+}
diff --git a/stubs/Symfony/Component/Form/AbstractType.stub b/stubs/Symfony/Component/Form/AbstractType.stub
index da2b1439..e99b746c 100644
--- a/stubs/Symfony/Component/Form/AbstractType.stub
+++ b/stubs/Symfony/Component/Form/AbstractType.stub
@@ -11,6 +11,7 @@ abstract class AbstractType implements FormTypeInterface
 {
 
 	/**
+	 * @param FormBuilderInterface<TData|null> $builder
 	 * @param array<string, mixed> $options
 	 */
 	public function buildForm(FormBuilderInterface $builder, array $options): void;
diff --git a/stubs/Symfony/Component/Form/FormBuilderInterface.stub b/stubs/Symfony/Component/Form/FormBuilderInterface.stub
index 5173bb64..fe578c50 100644
--- a/stubs/Symfony/Component/Form/FormBuilderInterface.stub
+++ b/stubs/Symfony/Component/Form/FormBuilderInterface.stub
@@ -3,9 +3,17 @@
 namespace Symfony\Component\Form;
 
 /**
- * @extends \Traversable<int, \Symfony\Component\Form\FormBuilderInterface>
+ * @template TData
+ *
+ * @extends \Traversable<int, \Symfony\Component\Form\FormBuilderInterface<mixed>>
+ * @extends FormConfigBuilderInterface<TData>
  */
-interface FormBuilderInterface extends \Traversable
+interface FormBuilderInterface extends \Traversable, \Countable, FormConfigBuilderInterface
 {
 
+    /**
+     * @return FormInterface<TData|null>
+     */
+    public function getForm(): FormInterface;
+
 }
diff --git a/stubs/Symfony/Component/Form/FormConfigBuilderInterface.stub b/stubs/Symfony/Component/Form/FormConfigBuilderInterface.stub
new file mode 100644
index 00000000..a167ce43
--- /dev/null
+++ b/stubs/Symfony/Component/Form/FormConfigBuilderInterface.stub
@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\Form;
+
+/**
+ * @template TData
+ *
+ * @extends FormConfigInterface<TData>
+ */
+interface FormConfigBuilderInterface extends FormConfigInterface
+{
+
+}
diff --git a/stubs/Symfony/Component/Form/FormConfigInterface.stub b/stubs/Symfony/Component/Form/FormConfigInterface.stub
new file mode 100644
index 00000000..942d467b
--- /dev/null
+++ b/stubs/Symfony/Component/Form/FormConfigInterface.stub
@@ -0,0 +1,16 @@
+<?php
+
+namespace Symfony\Component\Form;
+
+/**
+ * @template TData
+ */
+interface FormConfigInterface
+{
+
+    /**
+     * @return TData
+     */
+    public function getData(): mixed;
+
+}
diff --git a/stubs/Symfony/Component/Form/FormTypeExtensionInterface.stub b/stubs/Symfony/Component/Form/FormTypeExtensionInterface.stub
index 234d1b2e..a03d5e1c 100644
--- a/stubs/Symfony/Component/Form/FormTypeExtensionInterface.stub
+++ b/stubs/Symfony/Component/Form/FormTypeExtensionInterface.stub
@@ -8,6 +8,7 @@ namespace Symfony\Component\Form;
 interface FormTypeExtensionInterface
 {
     /**
+     * @param FormBuilderInterface<TData|null> $builder
      * @param array<string, mixed> $options
      */
     public function buildForm(FormBuilderInterface $builder, array $options): void;
diff --git a/stubs/Symfony/Component/Form/FormTypeInterface.stub b/stubs/Symfony/Component/Form/FormTypeInterface.stub
index 2f745283..8536656a 100644
--- a/stubs/Symfony/Component/Form/FormTypeInterface.stub
+++ b/stubs/Symfony/Component/Form/FormTypeInterface.stub
@@ -8,6 +8,7 @@ namespace Symfony\Component\Form;
 interface FormTypeInterface
 {
     /**
+     * @param FormBuilderInterface<TData|null> $builder
      * @param array<string, mixed> $options
      */
     public function buildForm(FormBuilderInterface $builder, array $options): void;
diff --git a/tests/Type/Symfony/ExtensionTest.php b/tests/Type/Symfony/ExtensionTest.php
index 879abb5d..73eb49b7 100644
--- a/tests/Type/Symfony/ExtensionTest.php
+++ b/tests/Type/Symfony/ExtensionTest.php
@@ -57,6 +57,15 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/FormInterface_getErrors.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/cache.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/form_data_type.php');
+
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/with-configuration/WithConfigurationExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/without-configuration/WithoutConfigurationExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/anonymous/AnonymousExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/ignore-implemented/IgnoreImplementedExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/multiple-types/MultipleTypes.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/with-configuration-with-constructor/WithConfigurationWithConstructorExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/with-configuration-with-constructor-optional-params/WithConfigurationWithConstructorOptionalParamsExtension.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/extension/with-configuration-with-constructor-required-params/WithConfigurationWithConstructorRequiredParamsExtension.php');
 	}
 
 	/**
diff --git a/tests/Type/Symfony/data/extension/anonymous/AnonymousExtension.php b/tests/Type/Symfony/data/extension/anonymous/AnonymousExtension.php
new file mode 100644
index 00000000..1e33cb37
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/anonymous/AnonymousExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\Anonymous;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Extension\Extension;
+
+new class extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container)
+	{
+		\PHPStan\Testing\assertType(
+			'null',
+			$this->getConfiguration($configs, $container)
+		);
+	}
+};
diff --git a/tests/Type/Symfony/data/extension/ignore-implemented/IgnoreImplementedExtension.php b/tests/Type/Symfony/data/extension/ignore-implemented/IgnoreImplementedExtension.php
new file mode 100644
index 00000000..614431f2
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/ignore-implemented/IgnoreImplementedExtension.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\IgnoreImplemented;
+
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class IgnoreImplementedExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			'Symfony\Component\Config\Definition\ConfigurationInterface|null',
+			$this->getConfiguration($configs, $container)
+		);
+	}
+
+	public function getConfiguration(array $config, ContainerBuilder $container): ?ConfigurationInterface
+	{
+		return null;
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/multiple-types/MultipleTypes.php b/tests/Type/Symfony/data/extension/multiple-types/MultipleTypes.php
new file mode 100644
index 00000000..77c44003
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/multiple-types/MultipleTypes.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\MultipleTypes;
+
+use PHPStan\Type\Symfony\Extension\WithConfiguration\WithConfigurationExtension;
+use PHPStan\Type\Symfony\Extension\WithoutConfiguration\WithoutConfigurationExtension;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+
+/**
+ * @param WithConfigurationExtension|WithoutConfigurationExtension $extension
+ */
+function test($extension, array $configs, ContainerBuilder $container)
+{
+	\PHPStan\Testing\assertType(
+		'PHPStan\Type\Symfony\Extension\WithConfiguration\Configuration|null',
+		$extension->getConfiguration($configs, $container)
+	);
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/Configuration.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/Configuration.php
new file mode 100644
index 00000000..4ff16c39
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/Configuration.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructorOptionalParams;
+
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+class Configuration implements ConfigurationInterface
+{
+	public function __construct($foo = null)
+	{
+	}
+
+	public function getConfigTreeBuilder()
+	{
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/WithConfigurationWithConstructorOptionalParamsExtension.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/WithConfigurationWithConstructorOptionalParamsExtension.php
new file mode 100644
index 00000000..56545350
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-optional-params/WithConfigurationWithConstructorOptionalParamsExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructorOptionalParams;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class WithConfigurationWithConstructorOptionalParamsExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			Configuration::class,
+			$this->getConfiguration($configs, $container)
+		);
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/Configuration.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/Configuration.php
new file mode 100644
index 00000000..b9d5bcc1
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/Configuration.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructorRequiredParams;
+
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+class Configuration implements ConfigurationInterface
+{
+	public function __construct($foo)
+	{
+	}
+
+	public function getConfigTreeBuilder()
+	{
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/WithConfigurationWithConstructorRequiredParamsExtension.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/WithConfigurationWithConstructorRequiredParamsExtension.php
new file mode 100644
index 00000000..ccc8b992
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor-required-params/WithConfigurationWithConstructorRequiredParamsExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructorRequiredParams;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class WithConfigurationWithConstructorRequiredParamsExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			'null',
+			$this->getConfiguration($configs, $container)
+		);
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor/Configuration.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor/Configuration.php
new file mode 100644
index 00000000..8eea9eb9
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor/Configuration.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructor;
+
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+class Configuration implements ConfigurationInterface
+{
+	public function __construct()
+	{
+	}
+
+	public function getConfigTreeBuilder()
+	{
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration-with-constructor/WithConfigurationWithConstructorExtension.php b/tests/Type/Symfony/data/extension/with-configuration-with-constructor/WithConfigurationWithConstructorExtension.php
new file mode 100644
index 00000000..7b5a2daf
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration-with-constructor/WithConfigurationWithConstructorExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfigurationWithConstructor;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class WithConfigurationWithConstructorExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			Configuration::class,
+			$this->getConfiguration($configs, $container)
+		);
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration/Configuration.php b/tests/Type/Symfony/data/extension/with-configuration/Configuration.php
new file mode 100644
index 00000000..4e8c51b5
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration/Configuration.php
@@ -0,0 +1,12 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfiguration;
+
+use Symfony\Component\Config\Definition\ConfigurationInterface;
+
+class Configuration implements ConfigurationInterface
+{
+	public function getConfigTreeBuilder()
+	{
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/with-configuration/WithConfigurationExtension.php b/tests/Type/Symfony/data/extension/with-configuration/WithConfigurationExtension.php
new file mode 100644
index 00000000..9b809841
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/with-configuration/WithConfigurationExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithConfiguration;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class WithConfigurationExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			Configuration::class,
+			$this->getConfiguration($configs, $container)
+		);
+	}
+}
diff --git a/tests/Type/Symfony/data/extension/without-configuration/WithoutConfigurationExtension.php b/tests/Type/Symfony/data/extension/without-configuration/WithoutConfigurationExtension.php
new file mode 100644
index 00000000..dccec3e2
--- /dev/null
+++ b/tests/Type/Symfony/data/extension/without-configuration/WithoutConfigurationExtension.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace PHPStan\Type\Symfony\Extension\WithoutConfiguration;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use \Symfony\Component\DependencyInjection\Extension\Extension;
+
+class WithoutConfigurationExtension extends Extension
+{
+	public function load(array $configs, ContainerBuilder $container): void
+	{
+		\PHPStan\Testing\assertType(
+			'null',
+			$this->getConfiguration($configs, $container)
+		);
+	}
+}
diff --git a/tests/Type/Symfony/data/form_data_type.php b/tests/Type/Symfony/data/form_data_type.php
index 524a5b7c..e0cefb88 100644
--- a/tests/Type/Symfony/data/form_data_type.php
+++ b/tests/Type/Symfony/data/form_data_type.php
@@ -29,6 +29,9 @@ class DataClassType extends AbstractType
 
 	public function buildForm(FormBuilderInterface $builder, array $options): void
 	{
+		assertType('GenericFormDataType\DataClass|null', $builder->getData());
+		assertType('GenericFormDataType\DataClass|null', $builder->getForm()->getData());
+
 		$builder
 			->add('foo', NumberType::class)
 			->add('bar', TextType::class)