Joe Cahill (Irish: Seosamh Ó Cathail; 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.