diff --git a/onnxruntime/core/graph/graph_proto_serializer.cc b/onnxruntime/core/graph/graph_proto_serializer.cc
index c8da2461a3..aefad28eb3 100644
--- a/onnxruntime/core/graph/graph_proto_serializer.cc
+++ b/onnxruntime/core/graph/graph_proto_serializer.cc
@@ -9,7 +9,7 @@ void GraphViewerToProto(const GraphViewer& graph_view,
                         ONNX_NAMESPACE::GraphProto& graph_proto,
                         bool include_initializer,
                         bool include_outer_scope_args,
-                        ExecutionOrder order = ExecutionOrder::DEFAULT) {
+                        ExecutionOrder order) {
   graph_proto.set_name(graph_view.Name());
   graph_proto.set_doc_string(graph_view.Description());
 
diff --git a/onnxruntime/core/graph/graph_proto_serializer.h b/onnxruntime/core/graph/graph_proto_serializer.h
index 43027ef704..ce21e1b609 100644
--- a/onnxruntime/core/graph/graph_proto_serializer.h
+++ b/onnxruntime/core/graph/graph_proto_serializer.h
@@ -11,5 +11,5 @@ void GraphViewerToProto(const GraphViewer& graph_view,
                         ONNX_NAMESPACE::GraphProto& graph_proto,
                         bool include_initializer,
                         bool include_outer_scope_args,
-                        ExecutionOrder order);
+                        ExecutionOrder order = ExecutionOrder::DEFAULT);
 }  // namespace onnxruntime