George Clancy, also known as Seoirse Clancy (1881 – 7 March 1921), was an Irish nationalist politician and Mayor of Limerick. He was shot dead in Limerick by the Black and Tans in 1921 during the Anglo-Irish conflict (1919–1922). The previous Mayor, Michael O'Callaghan, was murdered on the same night by the same group.
Clancy was born at Grange, County Limerick. He was educated at Crescent College, Limerick, and thereafter at the Catholic University in St Stephen's Green, now University College, Dublin. Among his friends at the university were James Joyce, Francis Sheehy-Skeffington and Tom Kettle. He helped form a branch of the Gaelic League at college and persuaded his friends, including Joyce, to take lessons in Irish. He played hurling and was a good friend of Michael Cusack. With Arthur Griffin he joined the Celtic Literary Society.
He graduated in 1904 and found a teaching position at Clongowes Wood College. Due to ill health he had to return to his home at Grange. In 1908 he came to Limerick City to teach Irish. In 1913 he joined the Irish Volunteers. In 1915 he married Máire Killeen, a teacher. After the 1916 Rising he was arrested and imprisoned in Cork, but after a hunger strike was released before he came to trial.
He was elected Sinn Fein Mayor of Limerick in 1921. On the night of the 6 March 1921 three Auxiliaries came to his house and one of them shot him, injuring him fatally. His wife was injured in the attack. One of his killers was later said to be George Nathan who died in the Spanish Civil War.