diff --git a/Source/Core/Core/MemoryWatcher.cpp b/Source/Core/Core/MemoryWatcher.cpp
index ecce7aa714..0f8776c072 100644
--- a/Source/Core/Core/MemoryWatcher.cpp
+++ b/Source/Core/Core/MemoryWatcher.cpp
@@ -4,6 +4,7 @@
 
 #include <fstream>
 #include <iostream>
+#include <unistd.h>
 
 #include "Common/FileUtil.h"
 #include "Common/Thread.h"