diff --git a/Alc/helpers.c b/Alc/helpers.c
index e9eb5faf..7f6349b3 100644
--- a/Alc/helpers.c
+++ b/Alc/helpers.c
@@ -41,6 +41,7 @@
 #endif
 
 #ifdef __FreeBSD__
+#include <sys/types.h>
 #include <sys/sysctl.h>
 #endif