diff --git a/DependencyInjection/TrikoderOAuth2Extension.php b/DependencyInjection/TrikoderOAuth2Extension.php
index ed595dc7..9ca20cec 100644
--- a/DependencyInjection/TrikoderOAuth2Extension.php
+++ b/DependencyInjection/TrikoderOAuth2Extension.php
@@ -41,6 +41,7 @@
 use Trikoder\Bundle\OAuth2Bundle\Manager\ScopeManagerInterface;
 use Trikoder\Bundle\OAuth2Bundle\Model\Scope as ScopeModel;
 use Trikoder\Bundle\OAuth2Bundle\Security\Authentication\Token\OAuth2TokenFactory;
+use Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker\DoctrineCredentialsRevoker;
 
 final class TrikoderOAuth2Extension extends Extension implements PrependExtensionInterface, CompilerPassInterface
 {
@@ -268,6 +269,11 @@ private function configureDoctrinePersistence(ContainerBuilder $container, array
             ->replaceArgument('$entityManager', $entityManager)
         ;
 
+        $container
+            ->getDefinition(DoctrineCredentialsRevoker::class)
+            ->replaceArgument('$entityManager', $entityManager)
+        ;
+
         $container->setParameter('trikoder.oauth2.persistence.doctrine.enabled', true);
         $container->setParameter('trikoder.oauth2.persistence.doctrine.manager', $entityManagerName);
     }
diff --git a/Manager/ClientManagerInterface.php b/Manager/ClientManagerInterface.php
index 71e6d34a..35169386 100644
--- a/Manager/ClientManagerInterface.php
+++ b/Manager/ClientManagerInterface.php
@@ -5,11 +5,10 @@
 namespace Trikoder\Bundle\OAuth2Bundle\Manager;
 
 use Trikoder\Bundle\OAuth2Bundle\Model\Client;
+use Trikoder\Bundle\OAuth2Bundle\Service\ClientFinderInterface;
 
-interface ClientManagerInterface
+interface ClientManagerInterface extends ClientFinderInterface
 {
-    public function find(string $identifier): ?Client;
-
     public function save(Client $client): void;
 
     public function remove(Client $client): void;
diff --git a/Resources/config/doctrine/model/AccessToken.orm.xml b/Resources/config/doctrine/model/AccessToken.orm.xml
index 192c6d9c..10886306 100644
--- a/Resources/config/doctrine/model/AccessToken.orm.xml
+++ b/Resources/config/doctrine/model/AccessToken.orm.xml
@@ -17,5 +17,8 @@
         <many-to-one field="client" target-entity="Trikoder\Bundle\OAuth2Bundle\Model\Client">
             <join-column name="client" referenced-column-name="identifier" nullable="false" on-delete="CASCADE" />
         </many-to-one>
+        <indexes>
+            <index columns="userIdentifier" />
+        </indexes>
     </entity>
 </doctrine-mapping>
diff --git a/Resources/config/doctrine/model/AuthorizationCode.orm.xml b/Resources/config/doctrine/model/AuthorizationCode.orm.xml
index f3930596..58eafedd 100644
--- a/Resources/config/doctrine/model/AuthorizationCode.orm.xml
+++ b/Resources/config/doctrine/model/AuthorizationCode.orm.xml
@@ -17,5 +17,8 @@
         <many-to-one field="client" target-entity="Trikoder\Bundle\OAuth2Bundle\Model\Client">
             <join-column name="client" referenced-column-name="identifier" nullable="false" />
         </many-to-one>
+        <indexes>
+            <index columns="userIdentifier" />
+        </indexes>
     </entity>
 </doctrine-mapping>
diff --git a/Resources/config/services.xml b/Resources/config/services.xml
index d2260595..0a137bf0 100644
--- a/Resources/config/services.xml
+++ b/Resources/config/services.xml
@@ -4,6 +4,8 @@
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
     <services>
+        <service id="Trikoder\Bundle\OAuth2Bundle\Service\ClientFinderInterface" alias="Trikoder\Bundle\OAuth2Bundle\Manager\ClientManagerInterface" />
+
         <!-- The league repositories -->
         <service id="Trikoder\Bundle\OAuth2Bundle\League\Repository\ClientRepository">
             <argument type="service" id="Trikoder\Bundle\OAuth2Bundle\Manager\ClientManagerInterface" />
diff --git a/Resources/config/storage/doctrine.xml b/Resources/config/storage/doctrine.xml
index 90a7f617..a3b2f732 100644
--- a/Resources/config/storage/doctrine.xml
+++ b/Resources/config/storage/doctrine.xml
@@ -12,6 +12,11 @@
         <service id="Trikoder\Bundle\OAuth2Bundle\Manager\AuthorizationCodeManagerInterface" alias="Trikoder\Bundle\OAuth2Bundle\Manager\Doctrine\AuthorizationCodeManager" />
 
         <!-- Services -->
+        <service id="Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevokerInterface" alias="Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker\DoctrineCredentialsRevoker" />
+        <service id="Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker\DoctrineCredentialsRevoker">
+            <argument key="$entityManager" />
+        </service>
+
         <service id="Trikoder\Bundle\OAuth2Bundle\Manager\Doctrine\ClientManager">
             <argument key="$entityManager" />
         </service>
diff --git a/Service/ClientFinderInterface.php b/Service/ClientFinderInterface.php
new file mode 100644
index 00000000..8e298cdf
--- /dev/null
+++ b/Service/ClientFinderInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Trikoder\Bundle\OAuth2Bundle\Service;
+
+use Trikoder\Bundle\OAuth2Bundle\Model\Client;
+
+/**
+ * @api
+ */
+interface ClientFinderInterface
+{
+    public function find(string $identifier): ?Client;
+}
diff --git a/Service/CredentialsRevoker/DoctrineCredentialsRevoker.php b/Service/CredentialsRevoker/DoctrineCredentialsRevoker.php
new file mode 100644
index 00000000..9158e706
--- /dev/null
+++ b/Service/CredentialsRevoker/DoctrineCredentialsRevoker.php
@@ -0,0 +1,101 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker;
+
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\Security\Core\User\UserInterface;
+use Trikoder\Bundle\OAuth2Bundle\Model\AccessToken;
+use Trikoder\Bundle\OAuth2Bundle\Model\AuthorizationCode;
+use Trikoder\Bundle\OAuth2Bundle\Model\Client;
+use Trikoder\Bundle\OAuth2Bundle\Model\RefreshToken;
+use Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevokerInterface;
+
+final class DoctrineCredentialsRevoker implements CredentialsRevokerInterface
+{
+    /**
+     * @var EntityManagerInterface
+     */
+    private $entityManager;
+
+    public function __construct(EntityManagerInterface $entityManager)
+    {
+        $this->entityManager = $entityManager;
+    }
+
+    public function revokeCredentialsForUser(UserInterface $user): void
+    {
+        $userIdentifier = $user->getUsername();
+
+        $this->entityManager->createQueryBuilder()
+            ->update(AccessToken::class, 'at')
+            ->set('at.revoked', true)
+            ->where('at.userIdentifier = :userIdentifier')
+            ->setParameter('userIdentifier', $userIdentifier)
+            ->getQuery()
+            ->execute();
+
+        $queryBuilder = $this->entityManager->createQueryBuilder();
+        $queryBuilder
+            ->update(RefreshToken::class, 'rt')
+            ->set('rt.revoked', true)
+            ->where($queryBuilder->expr()->in(
+                'rt.accessToken',
+                $this->entityManager->createQueryBuilder()
+                    ->select('at.identifier')
+                    ->from(AccessToken::class, 'at')
+                    ->where('at.userIdentifier = :userIdentifier')
+                    ->getDQL()
+            ))
+            ->setParameter('userIdentifier', $userIdentifier)
+            ->getQuery()
+            ->execute();
+
+        $this->entityManager->createQueryBuilder()
+            ->update(AuthorizationCode::class, 'ac')
+            ->set('ac.revoked', true)
+            ->where('ac.userIdentifier = :userIdentifier')
+            ->setParameter('userIdentifier', $userIdentifier)
+            ->getQuery()
+            ->execute();
+    }
+
+    public function revokeCredentialsForClient(Client $client): void
+    {
+        $doctrineClient = $this->entityManager
+            ->getRepository(Client::class)
+            ->findOneBy(['identifier' => $client->getIdentifier()]);
+
+        $this->entityManager->createQueryBuilder()
+            ->update(AccessToken::class, 'at')
+            ->set('at.revoked', true)
+            ->where('at.client = :client')
+            ->setParameter('client', $doctrineClient)
+            ->getQuery()
+            ->execute();
+
+        $queryBuilder = $this->entityManager->createQueryBuilder();
+        $queryBuilder->update(RefreshToken::class, 'rt')
+            ->set('rt.revoked', true)
+            ->where($queryBuilder->expr()->in(
+                'rt.accessToken',
+                $this->entityManager->createQueryBuilder()
+                    ->select('at.identifier')
+                    ->from(AccessToken::class, 'at')
+                    ->where('at.client = :client')
+                    ->getDQL()
+            ))
+            ->setParameter('client', $doctrineClient)
+            ->getQuery()
+            ->execute();
+
+        $this->entityManager->createQueryBuilder()
+            ->update(AuthorizationCode::class, 'ac')
+            ->set('ac.revoked', true)
+            ->where('ac.client = :client')
+            ->setParameter('client', $doctrineClient)
+            ->getQuery()
+            ->execute();
+    }
+}
diff --git a/Service/CredentialsRevokerInterface.php b/Service/CredentialsRevokerInterface.php
new file mode 100644
index 00000000..65cd7d9e
--- /dev/null
+++ b/Service/CredentialsRevokerInterface.php
@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Trikoder\Bundle\OAuth2Bundle\Service;
+
+use Symfony\Component\Security\Core\User\UserInterface;
+use Trikoder\Bundle\OAuth2Bundle\Model\Client;
+
+/**
+ * Service responsible for revoking credentials on client-level and user-level.
+ * Credentials = access tokens, refresh tokens and authorization codes.
+ *
+ * @api
+ */
+interface CredentialsRevokerInterface
+{
+    public function revokeCredentialsForUser(UserInterface $user): void;
+
+    public function revokeCredentialsForClient(Client $client): void;
+}
diff --git a/Tests/Acceptance/DoctrineCredentialsRevokerTest.php b/Tests/Acceptance/DoctrineCredentialsRevokerTest.php
new file mode 100644
index 00000000..d03a2d05
--- /dev/null
+++ b/Tests/Acceptance/DoctrineCredentialsRevokerTest.php
@@ -0,0 +1,112 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Trikoder\Bundle\OAuth2Bundle\Tests\Acceptance;
+
+use DateTimeImmutable;
+use Doctrine\ORM\EntityManagerInterface;
+use Trikoder\Bundle\OAuth2Bundle\Model\AccessToken;
+use Trikoder\Bundle\OAuth2Bundle\Model\AuthorizationCode;
+use Trikoder\Bundle\OAuth2Bundle\Model\Client;
+use Trikoder\Bundle\OAuth2Bundle\Model\RefreshToken;
+use Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker\DoctrineCredentialsRevoker;
+use Trikoder\Bundle\OAuth2Bundle\Tests\Fixtures\FixtureFactory;
+
+/**
+ * @TODO   This should be in the Integration tests folder but the current tests infrastructure would need improvements first.
+ * @covers \Trikoder\Bundle\OAuth2Bundle\Service\CredentialsRevoker\DoctrineCredentialsRevoker
+ */
+final class DoctrineCredentialsRevokerTest extends AbstractAcceptanceTest
+{
+    public function testRevokesAllCredentialsForUser(): void
+    {
+        $userIdentifier = FixtureFactory::FIXTURE_USER;
+
+        /** @var EntityManagerInterface $em */
+        $em = $this->client->getContainer()->get('doctrine.orm.entity_manager');
+
+        $em->persist($client = new Client('client', 'secret'));
+
+        $authCode = $this->buildAuthCode('foo', '+1 minute', $client, $userIdentifier);
+        $accessToken = $this->buildAccessToken('bar', '+1 minute', $client, $userIdentifier);
+        $refreshToken = $this->buildRefreshToken('baz', '+1 minute', $accessToken);
+
+        $em->persist($authCode);
+        $em->persist($accessToken);
+        $em->persist($refreshToken);
+        $em->flush();
+
+        $revoker = new DoctrineCredentialsRevoker($em);
+
+        $revoker->revokeCredentialsForUser(FixtureFactory::createUser());
+
+        $em->refresh($authCode);
+        $em->refresh($accessToken);
+        $em->refresh($refreshToken);
+
+        $this->assertTrue($authCode->isRevoked());
+        $this->assertTrue($accessToken->isRevoked());
+        $this->assertTrue($refreshToken->isRevoked());
+    }
+
+    public function testRevokesAllCredentialsForClient(): void
+    {
+        /** @var EntityManagerInterface $em */
+        $em = $this->client->getContainer()->get('doctrine.orm.entity_manager');
+
+        $em->persist($client = new Client('acme', 'secret'));
+
+        $authCode = $this->buildAuthCode('foo', '+1 minute', $client, 'john');
+        $accessToken = $this->buildAccessToken('bar', '+1 minute', $client);
+        $refreshToken = $this->buildRefreshToken('baz', '+1 minute', $accessToken);
+
+        $em->persist($authCode);
+        $em->persist($accessToken);
+        $em->persist($refreshToken);
+        $em->flush();
+
+        $revoker = new DoctrineCredentialsRevoker($em);
+
+        $revoker->revokeCredentialsForClient($client);
+
+        $em->refresh($authCode);
+        $em->refresh($accessToken);
+        $em->refresh($refreshToken);
+
+        $this->assertTrue($authCode->isRevoked());
+        $this->assertTrue($accessToken->isRevoked());
+        $this->assertTrue($refreshToken->isRevoked());
+    }
+
+    private function buildRefreshToken(string $identifier, string $modify, AccessToken $accessToken): RefreshToken
+    {
+        return new RefreshToken(
+            $identifier,
+            new DateTimeImmutable($modify),
+            $accessToken
+        );
+    }
+
+    private function buildAccessToken(string $identifier, string $modify, Client $client, ?string $userIdentifier = null): AccessToken
+    {
+        return new AccessToken(
+            $identifier,
+            new DateTimeImmutable($modify),
+            $client,
+            $userIdentifier,
+            []
+        );
+    }
+
+    private function buildAuthCode(string $identifier, string $modify, Client $client, ?string $userIdentifier = null): AuthorizationCode
+    {
+        return new AuthorizationCode(
+            $identifier,
+            new DateTimeImmutable($modify),
+            $client,
+            $userIdentifier,
+            []
+        );
+    }
+}