diff --git a/modules/gltf/gltf_document.cpp b/modules/gltf/gltf_document.cpp
index adeebde5211..de3d50ebc08 100644
--- a/modules/gltf/gltf_document.cpp
+++ b/modules/gltf/gltf_document.cpp
@@ -4661,7 +4661,9 @@ Error GLTFDocument::_serialize_materials(Ref<GLTFState> p_state) {
 			extensions["KHR_materials_emissive_strength"] = mat_emissive_strength;
 			p_state->add_used_extension("KHR_materials_emissive_strength");
 		}
-		mat_dict["extensions"] = extensions;
+		if (!extensions.is_empty()) {
+			mat_dict["extensions"] = extensions;
+		}
 
 		_attach_meta_to_extras(material, mat_dict);
 		materials.push_back(mat_dict);