diff --git a/library/platform_util.c b/library/platform_util.c
index 9878cc2..f9fe4f5 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -45,7 +45,7 @@
 #include <string.h>
 
 #if defined(_WIN32)
-#include <Windows.h>
+#include <windows.h>
 #endif
 
 // Detect platforms known to support explicit_bzero()