Joseph Aloysius Sweeney (13 June 1897 – 25 November 1980) was an Irish politician and military commander. He fought in the Easter Rising in the GPO and was a member of the IRA during the war of independence.
Sweeney was born in Burtonport, a town in The Rosses, a district in the north-west of County Donegal. He received his secondary education at St. Enda's School in Rathfarnham, where Patrick Pearse was Headmaster.
As the Sinn Féin candidate, Sweeney was elected to the British House of Commons as Member of Parliament (MP) for West Donegal at the 1918 general election, defeating the sitting nationalist Hugh Law. He did not attend (aged 21, he would have been the youngest MP), and instead participated in the First Dáil. He is the second youngest ever TD.
In 1921 he was one of six Sinn Féin candidates elected unopposed to the House of Commons of Southern Ireland for Donegal. Again he did not attend and instead participated in the Second Dáil. In 1922 he was re-elected as a Pro-Treaty Sinn Féin candidate for Donegal and participated in the Third Dáil.
He served as a Major-General in the National Army during the Irish Civil War in the early 1920s.
Having spent most of his life in Dublin, he died in 1980 aged 83.