diff --git a/src/OpenApi/Serializer/OpenApiNormalizer.php b/src/OpenApi/Serializer/OpenApiNormalizer.php
index 8c8b90dfa7a..2636e02065c 100644
--- a/src/OpenApi/Serializer/OpenApiNormalizer.php
+++ b/src/OpenApi/Serializer/OpenApiNormalizer.php
@@ -59,6 +59,10 @@ private function objectToArray($object)
         }
 
         if ($object instanceof \ArrayObject) {
+            if (0 === $object->count()) {
+                return $object;
+            }
+
             return array_map([$this, 'objectToArray'], $object->getArrayCopy());
         }