Joseph William Mongan (4 March 1880 – 12 March 1951) was an Irish politician. He was an unsuccessful candidate at the June 1927 general election, but was elected to Dáil Éireann as a Cumann na nGaedheal Teachta Dála (TD) for the Galway constituency at the September 1927 general election. He was re-elected at the 1932 general election but lost his seat at the 1933 general election.