Lt-General William O'Callaghan (DSM) (Irish: Liam Ó Céallachgáin) [1] was an Irish Army officer. He attended graduated from the Military College, at The Curragh County Kildare. He is most famous for being the Commanding Officer of United Nations Interim Force in Lebanon for a period in the 1980s. He was also a recipient of the French Légion d'Honneur and the Lebanese National Cedar Decoration.[2]