diff --git a/examples/js/loaders/GLTFLoader.js b/examples/js/loaders/GLTFLoader.js
index 18b0e4fa0d9964da34997c9d5a83992f86602fa0..9727a2b6d5b874f50444cbc40e44419861448a06 100644
--- a/examples/js/loaders/GLTFLoader.js
+++ b/examples/js/loaders/GLTFLoader.js
@@ -1669,7 +1669,7 @@ THREE.GLTFLoader = ( function () {
 				// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#materialnormaltexture
 				_material.normalScale.x = -1;
 
-				_material.userData = material.extras;
+				if ( material.extras ) _material.userData = material.extras;
 
 				return _material;