diff --git a/net/mld/mld_query.c b/net/mld/mld_query.c
index 0c37c1ebb2..91db845e1b 100644
--- a/net/mld/mld_query.c
+++ b/net/mld/mld_query.c
@@ -38,6 +38,7 @@
 #include <nuttx/config.h>
 
 #include <stdbool.h>
+#include <string.h>
 #include <assert.h>
 #include <debug.h>