diff --git a/src/SchemaFactory.php b/src/SchemaFactory.php
index 2e7ac5e746..28fb46fdaf 100644
--- a/src/SchemaFactory.php
+++ b/src/SchemaFactory.php
@@ -382,8 +382,11 @@ public function createSchema(): Schema
         $errorRootTypeMapper = new FinalRootTypeMapper($recursiveTypeMapper);
         $rootTypeMapper = new BaseTypeMapper($errorRootTypeMapper, $recursiveTypeMapper, $topRootTypeMapper);
         $rootTypeMapper = new EnumTypeMapper($rootTypeMapper, $annotationReader, $symfonyCache, $nsList);
-        // Annotation support - deprecated
-        $rootTypeMapper = new MyCLabsEnumTypeMapper($rootTypeMapper, $annotationReader, $symfonyCache, $nsList);
+
+        if (class_exists(Enum::class)) {
+            // Annotation support - deprecated
+            $rootTypeMapper = new MyCLabsEnumTypeMapper($rootTypeMapper, $annotationReader, $symfonyCache, $nsList);
+        }
 
         if (! empty($this->rootTypeMapperFactories)) {
             $rootSchemaFactoryContext = new RootTypeMapperFactoryContext(