diff --git a/onnxruntime/test/onnx/heap_buffer.h b/onnxruntime/test/onnx/heap_buffer.h
index b4abf131b1..380a65b5aa 100644
--- a/onnxruntime/test/onnx/heap_buffer.h
+++ b/onnxruntime/test/onnx/heap_buffer.h
@@ -4,6 +4,7 @@
 #pragma once
 #include <vector>
 #include <memory>
+#include <stdlib.h>
 
 namespace onnxruntime {
 namespace test {