The Green Slime (ガンマー第3号 宇宙大作戦, Ganmā Daisan Gō: Uchū Daisakusen) is a 1968 science fiction film directed by Kinji Fukasaku and produced by Walter Manley and Ivan Reiner. It was written by William Finger, Tom Rowe and Charles Sinclair from a story by Reiner. The film was shot in Japan with a Japanese director and film crew, but with the non-Japanese starring cast of Robert Horton, Richard Jaeckel and Luciana Paluzzi.

After destroying a huge asteroid that was on a rapid collision course with Earth, a group of astronauts discover they have accidentally returned to their space station with an alien slime creature that feeds on radiation and can reproduce rapidly from its own blood.