18 Stone of Idiot is a British television programme broadcast on Channel 4 in 2005 designed as a vehicle for Johnny Vegas and produced by Chris Evans.

The first show was broadcast on 27 May 2005 and a further five episodes were broadcast weekly thereafter. Vegas' stated intention was to make a programme "so ridiculous that there was no way they'd recommission it."

Each show had one primary guest whom Vegas interviewed, and who were further involved in various stunts and skits.