diff --git a/lib/md5.c b/lib/md5.c
index eda1fe80b6..ada2d37e6f 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -86,7 +86,7 @@ static void MD5_Final(unsigned char digest[16], MD5_CTX * ctx)
 
 #elif defined(_WIN32)
 
-#include <WinCrypt.h>
+#include <wincrypt.h>
 
 typedef struct {
   HCRYPTPROV hCryptProv;
diff --git a/src/tool_metalink.c b/src/tool_metalink.c
index 9199b50f78..279a626cb1 100644
--- a/src/tool_metalink.c
+++ b/src/tool_metalink.c
@@ -64,7 +64,7 @@
 #elif defined(_WIN32)
 /* For Windows: If no other crypto library is provided, we fallback
    to the hash functions provided within the Microsoft Windows CryptoAPI */
-#  include <WinCrypt.h>
+#  include <wincrypt.h>
 /* Custom structure in order to store the required provider and hash handle */
 struct win32_crypto_hash {
   HCRYPTPROV hCryptProv;