Sir Thomas Fitz-Christopher Plunket (c.1407–1471) was a leading Irish lawyer and judge of the fifteenth century who held office as Lord Chief Justice of Ireland. He was an ancestor of the Duke of Wellington in the female line. His second marriage to the heiress Marian Cruise inspired the ballad The Song of Mary Cruys.

The Court of King's Bench was one of the senior courts of common law in Ireland. It was a mirror of the Court of King's Bench in England. The Lord Chief Justice was the most senior judge in the court, and the second most senior Irish judge under English rule and later when Ireland became part of the United Kingdom. Additionally, for a brief period between 1922 and 1924, the Lord Chief Justice of Ireland was the most senior judge in the Irish Free State.