diff --git a/src/process_iterator_apple.c b/src/process_iterator_apple.c
index 0674337..f289f80 100644
--- a/src/process_iterator_apple.c
+++ b/src/process_iterator_apple.c
@@ -30,6 +30,8 @@
 #include <errno.h>
 #include <libproc.h>
 #include "process_iterator.h"
+#include <unistd.h>
+#include <sys/sysctl.h>
 
 static int unique_nonzero_pids(pid_t *arr_in, int len_in, pid_t *arr_out)
 {