diff --git a/tweetnacl/contrib/randombytes/winrandom.c b/tweetnacl/contrib/randombytes/winrandom.c
index 4d649f74..54d8d58e 100644
--- a/tweetnacl/contrib/randombytes/winrandom.c
+++ b/tweetnacl/contrib/randombytes/winrandom.c
@@ -1,5 +1,5 @@
 #include <windows.h>
-#include <WinCrypt.h>
+#include <wincrypt.h>
 
 #define NCP ((HCRYPTPROV) 0)