diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 6a45838fd1b3..d1e309de88b6 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -1785,6 +1785,9 @@ static int nl802154_add_llsec_dev(struct sk_buff *skb, struct genl_info *info)
 	struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
 	struct ieee802154_llsec_device dev_desc;
 
+	if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
+		return -EOPNOTSUPP;
+
 	if (ieee802154_llsec_parse_device(info->attrs[NL802154_ATTR_SEC_DEVICE],
 					  &dev_desc) < 0)
 		return -EINVAL;