diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c
index cab1b5ac0c..a0a7ac0f9e 100644
--- a/src/udev/udev-event.c
+++ b/src/udev/udev-event.c
@@ -7,6 +7,7 @@
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
 #include "sd-event.h"