Joe Cahill (; 19 May 1920 – 23 July 2004) was a prominent figure in the Irish republican movement in Northern Ireland and former chief of staff of the Provisional Irish Republican Army (IRA). He joined a junior-republican movement, Na Fianna Eireann, in 1937 and the following year, joined the Irish Republican Army. In 1969, Cahill was a key figure in the founding of the Provisional Irish Republican Army. During his time in the Provisional IRA, Cahill helped import weapons and raise financial support. He served as the chief of staff in 1972, but was arrested the following year when a ship importing weapons was intercepted.