Father Nicholas Sheehy (1728–1766) was an 18th-century Irish Roman Catholic priest who was executed on the charge of being an accessory to murder. Father Sheehy was a prominent and vocal opponent of the Penal Laws, which subjected the whole Catholic Church in Ireland to religious persecution, and as a vocal activist for Catholic Emancipation. His conviction was widely regarded as a judicial murder and was cited long afterwards as Irish jargon for a miscarriage of justice. Fr. Nicholas Sheehy is currently regarded as one of the Irish Catholic Martyrs.

The Main Guard is a National Monument and former courthouse located in Clonmel, Ireland.