Rud Hud Hudibras (Welsh: Run baladr bras) was a legendary king of the Britons as recounted by Geoffrey of Monmouth. He was the son of King Leil and ruled during a civil war.

During the waning years of Leil's reign, the kingdom of the Britons became unstable, and civil war broke out. Rud Hud Hudibras became king after his father's death and reigned for 39 years, ending the civil war and restoring peace to the kingdom. During his reign, he founded Kaerreint, later renamed Canterbury by the Angles. He is also said to have founded Kaerguenit (Winchester) and Paladur Castle (Shaftesbury). He was succeeded by his son Bladud.

He was said to have reigned at the time Capys was king in Alba Longa and Haggai, Amos, Joel, and Azariah were prophesizing in Israel. Haggai began his ministry around 520 BC, whilst Amos is said to have prophesised during the reins of Uzziah of Judah and Jeroboam II, probably around 760 BC.