diff --git a/net/icmpv6/icmpv6_input.c b/net/icmpv6/icmpv6_input.c
index 1408f1d82a..62ef36068b 100644
--- a/net/icmpv6/icmpv6_input.c
+++ b/net/icmpv6/icmpv6_input.c
@@ -408,7 +408,7 @@ void icmpv6_input(FAR struct net_driver_s *dev, unsigned int iplen)
                   {
                     FAR struct icmpv6_mtu_s *mtuopt =
                                         (FAR struct icmpv6_mtu_s *)opt;
-                    dev->d_pktsize = mtuopt->mtu;
+                    dev->d_pktsize = NTOHL(mtuopt->mtu);
                   }
                   break;