Le Roi du Monde, a 1927 novel by René Guénon

Rex Mundi is Latin for King of the World. Rex Mundi may also refer to:

The King Kong Show, re-titled as King of the World: The King Kong Show in Japan

Rex Mundi (Dark Horse Comics), a comic book series

Rex Mundi (Malibu Comics), a fictional character in Malibu Comics' Ultraverse imprint

King of the World, the last track on Steely Dan's labum Countdown to Ecstasy

Rex Mundi High School, a former Catholic high school in Evansville, Indiana, USA

Richard Markle, a rotoscope artist who used then pen-name Rex mundi.

Cyrus the Great, so described on the Cyrus cylinder