Seán Hayes (1890 – 4 January 1968) was an Irish revolutionary and politician. He was a Fianna Fáil Teachta Dála (TD) for 10 years, and later a senator for 22 years.^[1]

Hayes was a member of the Irish Volunteers from 1916. During the Irish War of Independence, he joined the South Tipperary Brigade Active Service Unit (ASU) in Summer 1920 under the command of Seán Treacy, Ernie O'Malley and Dan Breen.^[2] He took part in several ambushes of British forces and attacks on Royal Irish Constabulary Barracks in counties Tipperary, Waterford and Kilkenny. During the Truce period, he was Battalion Commandant of 7 Battalion, South Tipperary Brigade, IRA.

Taking the anti-Treaty side in the Irish Civil War, Hayes took part in fighting against the National Army during the Battle of Dublin in late June-early July 1922, and was promoted to Brigade Commandant of South Tipperary Brigade, IRA. He took part in several attacks and ambushes of National forces in counties Tipperary and Kilkenny and was with Liam Lynch when he was killed in April 1923. Hayes was not captured and remained on the run until the end of the war. He later applied to the Irish government for a service pension under the Military Service Pensions Act, 1934 and was awarded nine years service in 1935 at Grade D for his service with the Irish Volunteers and the IRA between 1 April 1917 and 30 September 1923.^[2]

Hayes was first elected to Dáil Éireann at the June 1927 general election as a TD for the Tipperary constituency, and held the seat until his defeat at the 1937 general election. He stood again at the 1943 general election and at by-election in 1947, but never returned to the Dáil.^[3]

In the 1938 election to the reconstituted Seanad Éireann, he was elected by the Labour Panel, and held the seat at the further election later that year to the 3rd Seanad. He lost his seat at the 1943 Seanad election. He was re-elected by the Labour Panel at the 1948 election to the 6th Seanad, and at subsequent elections until he stepped down at the 1965 election.^[1] He died on 4 January 1968.^[4]