Mad Monty is a pirate who appeared as the quaternary antagonist in Muppet Treasure Island. Along with Polly Lobster and Clueless Morgan, he's one of the main conspirators and henchmen to Long John Silver. His eyes peek out from his grungy stovepipe hat.

Mad Monty has a penchant for violence. In the song "Sailing for Adventure", Monty says that he loves to hang his victims and watch their faces turn blue as they suffocate and "try to walk in the air". Later, in the song "Professional Pirate", Monty says he likes "taking things apart" as evidence he could have been a surgeon. His name and attitude imply that Monty might be a violent psychopath.

Mad Monty is the only pirate of which a PVC figure was made. He is sculpted with Polly Lobster on his hat.