Monster Island may refer to:

• Monster Isle, the Mole Man's base in the Marvel Comics canon introduced in "The Fantastic Four" #1 ^*
• Monsterland / Monster Island, home to a number of kaiju in the Godzilla series
• Monster Island, a play-by-mail game.
• Monster Island, the home of the monsters that periodically attack the City of Townsville in the Powerpuff Girls animated TV series
• Monster Island Studio, an Austin, TX-based recording studio used by U.S. anime distributor ADV Films until early 2005
• Monster Island (film), a 2004 made-for-TV movie.
• Monster Island (novel), a novel by David Wellington.
• Monster Island (Buffy/Angel novel) by Christopher Golden & Thomas E. Sniegoski

Fictional islands