Alexander Ernest Donnelly, known as Alex Donnelly (died 9 May 1958), was a nationalist politician and solicitor in Ireland. Donnelly studied at the Christian Brothers School in Omagh and the Royal University of Ireland. He was elected to Tyrone County Council in 1914, holding his seat until 1951, holding the post of council Chairman from 1920 to 1924. He was also a member of Omagh Urban District Council. In 1916, he was a founder member of Sinn Féin in the county, alongside Cahir Healy, and .