diff --git a/xpcom/glue/nsCRTGlue.cpp b/xpcom/glue/nsCRTGlue.cpp
index 3251e905de2..aaa9f98a40a 100644
--- a/xpcom/glue/nsCRTGlue.cpp
+++ b/xpcom/glue/nsCRTGlue.cpp
@@ -43,9 +43,12 @@
 #include "nsDebug.h"
 #include <string.h>
 #include <stdio.h>
-#include <io.h>
 #include <stdarg.h>
 
+#ifdef XP_WIN
+#include <io.h>
+#endif
+
 const char*
 NS_strspnp(const char *delims, const char *str)
 {