diff --git a/src/openbsd-compat/bcrypt_pbkdf.c b/src/openbsd-compat/bcrypt_pbkdf.c
index 0a07f9a..d841940 100644
--- a/src/openbsd-compat/bcrypt_pbkdf.c
+++ b/src/openbsd-compat/bcrypt_pbkdf.c
@@ -20,7 +20,9 @@
 #ifndef HAVE_BCRYPT_PBKDF
 
 #include <sys/types.h>
+#ifndef _WIN32
 #include <sys/param.h>
+#endif
 
 #ifdef HAVE_STDLIB_H
 # include <stdlib.h>