diff --git a/swaynag/main.c b/swaynag/main.c
index 854368e51..6b0b52361 100644
--- a/swaynag/main.c
+++ b/swaynag/main.c
@@ -1,4 +1,5 @@
 #define _XOPEN_SOURCE 500
+#include <stdlib.h>
 #include <signal.h>
 #include "log.h"
 #include "list.h"
diff --git a/swaynag/swaynag.c b/swaynag/swaynag.c
index 3966277d6..893f41e44 100644
--- a/swaynag/swaynag.c
+++ b/swaynag/swaynag.c
@@ -1,4 +1,5 @@
 #define _XOPEN_SOURCE 500
+#include <stdlib.h>
 #include <assert.h>
 #include <sys/stat.h>
 #include <sys/wait.h>