John Dinneen (23 March 1867 – 1 January 1942) was an Irish Farmers' Party politician. A farmer, he was first elected to Dáil Éireann at the 1922 general election as a Farmers' Party Teachta Dála (TD) for the Cork East and North East constituency. He was re-elected at the 1923 general election for the Cork East constituency. He lost his seat at the June 1927 general election. His nephew Liam Ahern served as a Fianna Fáil Senator and TD from 1957 to 1974 and his grand-nephew Michael Ahern, son of Liam Ahern, has been a Fianna Fáil TD for Cork East from 1982 to 2011. In June 1922 the Bishop of Cloyne Robert Browne, contributed £20 each to the election funds of Michael Hennessy and Dinneen, Commercial and Farmer pro-Treaty candidates respectively for the Cork East and North East constituency.