diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index a7cb28a78c6f0..6036516ddb9e5 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -1557,6 +1557,9 @@ static int nl802154_add_llsec_key(struct sk_buff *skb, struct genl_info *info)
 	struct ieee802154_llsec_key_id id = { };
 	u32 commands[NL802154_CMD_FRAME_NR_IDS / 32] = { };
 
+	if (wpan_dev->iftype == NL802154_IFTYPE_MONITOR)
+		return -EOPNOTSUPP;
+
 	if (!info->attrs[NL802154_ATTR_SEC_KEY] ||
 	    nla_parse_nested_deprecated(attrs, NL802154_KEY_ATTR_MAX, info->attrs[NL802154_ATTR_SEC_KEY], nl802154_key_policy, info->extack))
 		return -EINVAL;