diff --git a/core/lib/Drupal/Core/Entity/EntityType.php b/core/lib/Drupal/Core/Entity/EntityType.php
index f4c6d991d26..d0ad1961620 100644
--- a/core/lib/Drupal/Core/Entity/EntityType.php
+++ b/core/lib/Drupal/Core/Entity/EntityType.php
@@ -465,6 +465,7 @@ class EntityType extends PluginDefinition implements EntityTypeInterface {
       $handlers = $this->getHandlerClasses();
       return $nested ? $handlers[$handler_type][$nested] : $handlers[$handler_type];
     }
+    return NULL;
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
index b9eef7b9cd8..f281e27d5ef 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
@@ -167,6 +167,8 @@ class EntityTypeTest extends UnitTestCase {
     ]);
     $this->assertSame($controller, $entity_type->getHandlerClass('storage'));
     $this->assertSame($controller, $entity_type->getHandlerClass('form', 'default'));
+    $this->assertNull($entity_type->getHandlerClass('foo'));
+    $this->assertNull($entity_type->getHandlerClass('foo', 'bar'));
   }
 
   /**