Unknown World
- Taon: 1951
- Bansa: United States of America
- Genre: Adventure, Science Fiction
- Studio: Lippert Pictures
- Keyword: cave, exploration, scientific expedition, tunnel, underground lake, subterranean world, underground cavern, woman scientist, poison gas
- Direktor: Terry O. Morse
- Cast: Bruce Kellogg, Otto Waldis, Jim Bannon, Tom Handley, Dick Cogan, George Baxter