diff --git a/src/drivers/net/rtl8139.c b/src/drivers/net/rtl8139.c
index ff7de5c6..2dff324c 100644
--- a/src/drivers/net/rtl8139.c
+++ b/src/drivers/net/rtl8139.c
@@ -69,6 +69,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <gpxe/io.h>
 #include <errno.h>
 #include <unistd.h>