Thomas MacDonagh (Irish: Tomás Mac Donnchadha; 1 February 1878 – 3 May 1916) was an Irish political activist, poet, playwright, educationalist and revolutionary leader. He was one of the seven leaders of the Easter Rising of 1916, a signatory of the Proclamation of the Irish Republic and Commandant of the 2nd Battalion, Dublin Brigade of the Irish Volunteers, which fought in Jacob's biscuit factory.