diff --git a/include/onnxruntime/core/session/onnxruntime_c_api.h b/include/onnxruntime/core/session/onnxruntime_c_api.h
index 1f449db4e4..3d1fddd195 100644
--- a/include/onnxruntime/core/session/onnxruntime_c_api.h
+++ b/include/onnxruntime/core/session/onnxruntime_c_api.h
@@ -1,6 +1,10 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+// =====================================================================================================
+// NOTE: This header is PRE-RELEASE and subject to change. Please do not rely on this file not changing.
+// =====================================================================================================
+
 #pragma once
 #include <stdbool.h>
 #include <stdlib.h>