Peter Joseph Cleary (18 September 1950 – 15 April 1976) was an Irish republican and a leading member of the 1st Battalion of the Provisional Irish Republican Army (IRA)'s South Armagh Brigade. He held the rank of Staff Officer and served as the unit's treasurer. He was implicated by journalist and author Joe Tiernan in the killing of Ulster Defence Regiment (UDR) corporal and alleged Ulster Volunteer Force (UVF) member Robert McConnell.