diff --git a/tiny_gltf.h b/tiny_gltf.h
index ec98174..02030bc 100644
--- a/tiny_gltf.h
+++ b/tiny_gltf.h
@@ -7471,7 +7471,7 @@ static void SerializeGltfModel(Model *model, json &o) {
   }
 
   // Extensions used
-  if (model->extensionsUsed.size()) {
+  if (extensionsUsed.size()) {
     SerializeStringArrayProperty("extensionsUsed", extensionsUsed, o);
   }