Larry Grogan (Irish: Labhras Ó Gruagáin; 1899–1979) was an Irish republican activist. Born in Drogheda, Grogan joined the Irish Volunteers at the age of 18, which subsequently became part of the original Irish Republican Army (IRA). He was active in the Irish War of Independence, then in the Irish Civil War in the anti-treaty IRA. He was imprisoned in Mountjoy Prison in 1922, and was subsequently interned in the Curragh Camp, where he kept an autograph book, collecting signatures including that of Michael Hilliard.