Richard "the Iron" Bourke (Irish: Risdeárd an Iarainn Bourke; English: /bɜːrk/; BURK; d. 1583), 18th Mac William Íochtar (Lower Mac William), was an Irish chieftain and noble.

Bourke was a son of David de Búrca, 15th Mac William Íochtar, by his second wife, Finola Ni Flaithbertaigh.

In medieval Ireland, Richard was a rare name, most found in Norman-origin families like the Bourkes.

He was the father of several children, including Tibbot ne Long Bourke, 1st Viscount Mayo (23rd Mac William Íochtar).

During the uneven anglicisation of Ireland in the 1500s, by the policy of "Surrender and regrant", Richard signed an agreement with the Crown in 1581 which uniquely left him in autonomous control of his part of County Mayo.