diff --git a/UPGRADE-3.x.md b/UPGRADE-3.x.md
index bc688a8b225..5f97783c12c 100644
--- a/UPGRADE-3.x.md
+++ b/UPGRADE-3.x.md
@@ -4,6 +4,10 @@ UPGRADE 3.x
 UPGRADE FROM 3.xx to 3.xx
 =========================
 
+### Deprecated `AdminInterface::getValidator()` and  `AdminInterface::setValidator()` methods, `AbstractAdmin::$validator` property.
+
+Methods are deprecated without replacement.
+
 ### Sonata\AdminBundle\Admin\Pool
 
 - Passing a `Symfony\Component\PropertyAccess\PropertyAccessorInterface` instance as 4 argument instantiating
diff --git a/src/Admin/AbstractAdmin.php b/src/Admin/AbstractAdmin.php
index 96c0f968756..f6c1f14beb9 100644
--- a/src/Admin/AbstractAdmin.php
+++ b/src/Admin/AbstractAdmin.php
@@ -392,7 +392,11 @@ abstract class AbstractAdmin implements AdminInterface, DomainObjectInterface, A
     protected $securityHandler;
 
     /**
+     * NEXT_MAJOR: Remove this property.
+     *
      * @var ValidatorInterface
+     *
+     * @deprecated since sonata-project/admin-bundle 3.x and will be removed in 4.0
      */
     protected $validator;
 
@@ -2849,6 +2853,11 @@ public function id($model)
         return $this->getNormalizedIdentifier($model);
     }
 
+    /**
+     * NEXT_MAJOR: Remove this method.
+     *
+     * @deprecated since sonata-project/admin-bundle 3.x and will be removed in 4.0
+     */
     public function setValidator($validator)
     {
         // NEXT_MAJOR: Move ValidatorInterface check to method signature
@@ -2862,8 +2871,18 @@ public function setValidator($validator)
         $this->validator = $validator;
     }
 
+    /**
+     * NEXT_MAJOR: Remove this method.
+     *
+     * @deprecated since sonata-project/admin-bundle 3.x and will be removed in 4.0
+     */
     public function getValidator()
     {
+        @trigger_error(sprintf(
+            'The %s method is deprecated since version 3.x and will be removed in 4.0.',
+            __METHOD__
+        ), E_USER_DEPRECATED);
+
         return $this->validator;
     }
 
diff --git a/src/Admin/AdminInterface.php b/src/Admin/AdminInterface.php
index 6555e1398eb..69d0098a7d0 100644
--- a/src/Admin/AdminInterface.php
+++ b/src/Admin/AdminInterface.php
@@ -328,14 +328,22 @@ public function getNormalizedIdentifier($model);
     public function id($model);
 
     /**
+     * NEXT_MAJOR: remove this method.
+     *
      * @param ValidatorInterface $validator
      *
      * @return void
+     *
+     * @deprecated since sonata-project/admin-bundle 3.x and will be removed in 4.0
      */
     public function setValidator($validator);
 
     /**
+     * NEXT_MAJOR: remove this method.
+     *
      * @return ValidatorInterface
+     *
+     * @deprecated since sonata-project/admin-bundle 3.x and will be removed in 4.0
      */
     public function getValidator();
 
diff --git a/src/DependencyInjection/Compiler/AddDependencyCallsCompilerPass.php b/src/DependencyInjection/Compiler/AddDependencyCallsCompilerPass.php
index a4f580ef6e1..2c4f025bfeb 100644
--- a/src/DependencyInjection/Compiler/AddDependencyCallsCompilerPass.php
+++ b/src/DependencyInjection/Compiler/AddDependencyCallsCompilerPass.php
@@ -233,7 +233,7 @@ public function applyConfigurationFromAttribute(Definition $definition, array $a
             'translator',
             'configuration_pool',
             'router',
-            'validator',
+            'validator', //NEXT_MAJOR: Remove this line
             'security_handler',
             'menu_factory',
             'route_builder',
@@ -281,7 +281,7 @@ public function applyDefaults(ContainerBuilder $container, $serviceId, array $at
             'translator' => 'translator',
             'configuration_pool' => 'sonata.admin.pool',
             'route_generator' => 'sonata.admin.route.default_generator',
-            'validator' => 'validator',
+            'validator' => 'validator', //NEXT_MAJOR: Remove this line
             'security_handler' => 'sonata.admin.security.handler',
             'menu_factory' => 'knp_menu.factory',
             'route_builder' => 'sonata.admin.route.path_info'.
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index cbb3a0fca8e..c9905c7fa72 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -354,6 +354,7 @@ public function getConfigTreeBuilder()
                             ->scalarNode('translator')->defaultNull()->end()
                             ->scalarNode('configuration_pool')->defaultNull()->end()
                             ->scalarNode('route_generator')->defaultNull()->end()
+                            // NEXT_MAJOR: remove validator option
                             ->scalarNode('validator')->defaultNull()->end()
                             ->scalarNode('security_handler')->defaultNull()->end()
                             ->scalarNode('label')->defaultNull()->end()
diff --git a/tests/Admin/AdminTest.php b/tests/Admin/AdminTest.php
index c34c5c59031..fbdf3ce55c3 100644
--- a/tests/Admin/AdminTest.php
+++ b/tests/Admin/AdminTest.php
@@ -954,6 +954,11 @@ public function testGetFormTheme(): void
         $this->assertSame(['FooTheme'], $admin->getFormTheme());
     }
 
+    /**
+     * NEXT_MAJOR: remove this method.
+     *
+     * @group legacy
+     */
     public function testGetValidator(): void
     {
         $admin = new PostAdmin('sonata.post.admin.post', 'NewsBundle\Entity\Post', 'Sonata\NewsBundle\Controller\PostAdminController');
@@ -963,6 +968,9 @@ public function testGetValidator(): void
         $validator = $this->getMockForAbstractClass(ValidatorInterface::class);
 
         $admin->setValidator($validator);
+
+        $this->expectDeprecation('The Sonata\AdminBundle\Admin\AbstractAdmin::getValidator method is deprecated since version 3.x and will be removed in 4.0.');
+
         $this->assertSame($validator, $admin->getValidator());
     }
 
@@ -2840,6 +2848,7 @@ public function testAdminAvoidInifiniteLoop(): void
 
         $validator = $this->createMock(ValidatorInterface::class);
         $validator->method('getMetadataFor')->willReturn($this->createStub(MemberMetadata::class));
+
         $admin->setValidator($validator);
 
         $routeGenerator = $this->createStub(RouteGeneratorInterface::class);