Hubertus Martinus "Huub" Duyn (Dutch: Hubertus Martinus Duijn; born 1 September 1984 in Onderdijk, North Holland) is a Dutch racing cyclist, who currently rides for UCI Professional Continental team Roompot–Charles.
His best result to date was winning the Paris-Tours under 23 race.
In September 2014 it was announced that Duyn had signed with the new Team Roompot team for 2015.