Lost World, The Lost World or Lost Worlds may refer to:

• The Lost World (Doyle novel), 1912
• The Lost World (1925 film), a silent film set in South America
• The Lost World (1960 film), set in Venezuela
• The Lost World (1992 film), set in Africa
• The Lost World (1998 film), set in Mongolia
• The Lost World (2001 film), a BBC film
• The Lost World (TV series), or Sir Arthur Conan Doyle's The Lost World
• "The Lost World", a radio drama in the Radio Tales series

• The Lost World (Crichton novel), 1995
• The Lost World: Jurassic Park, a 1997 film
  • The Lost World: Jurassic Park (film score)
  • The Lost World: Jurassic Park (arcade game)
  • The Lost World: Jurassic Park (console game)
• The Lost World: Jurassic Park (handheld game)
• The Lost World: Jurassic Park (Sega Genesis game)
• The Lost World: Jurassic Park (pinball)
• Chaos Island: The Lost World, a video game

• Lost Worlds (TV series), a History Channel documentary series
• Il mondo perduto ('The lost world'), a compilation of short documentary films by Vittoria De Seta

• Forgotten Worlds (known as Lost Worlds in Japan), a 1988 arcade game
• The Lost World, a 1998 role-playing game for MSX2
• The History Channel: Lost Worlds, a Mac game, 2008
• Ricochet Lost Worlds, a video game
• Sonic Lost World, a 2013 video game
• Lost World (pinball), a pinball machine

• Lost Worlds (Carter short story collection), 1980
• Lost Worlds (Smith short story collection), 1944
• Lost Worlds (gamebook), by Alfred Leonardi, 1983
• Lost world, a subgenre of the fantasy or science fiction genres
• Lost World (manga), by Osamu Tezuka, 1948
• The Lost World, a poetry collection by Randall Jarrell

• The Lost World, a 2009 album by Pull Tiger Tail

• Lost World Caverns, West Virginia, U.S.

• All pages with titles containing lost world
• List of lost lands
• List of mythological places
• Lost city