diff --git a/tools/include/xen-sd-notify.h b/tools/include/xen-sd-notify.h
index 28c9b20f15..20441d0ec9 100644
--- a/tools/include/xen-sd-notify.h
+++ b/tools/include/xen-sd-notify.h
@@ -20,6 +20,7 @@
 #include <errno.h>
 #include <stddef.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <unistd.h>