Orion Publishing Group Ltd. is a British publishing company owned by parent company Hachette Livre, based in London. It was founded in 1991. Orion was responsible for publishing Aliens, Predator and Aliens vs. Predator novels in the United Kingdom between 1992 and 1997, under license from Bantam Books, who published the novels in the United States. Orion released these novels under the science-fiction imprint Millennium.
All of the novels published by Orion were adaptations of Dark Horse Comics comic book series, with just one exception — Aliens vs. Predator: Hunter's Planet was an original story. Following the release of Predator: Cold War in 1997, Orion ceased publishing Aliens/Predator/Aliens vs. Predator novels in the UK; as a result, the final three novels produced by Bantam (Aliens: Berserker, Predator: Big Game and Aliens vs. Predator: War) were never actually released there. In fact, subsequent novels by DH Press were likewise never published in the UK, meaning the next British novel release would not be until Titan Books published Alien: Out of the Shadows in 2014, a hiatus of 17 years.
- Aliens: Earth Hive by Steve Perry
- Aliens: Nightmare Asylum by Steve Perry
- Aliens: The Female War by Steve Perry and Stephani Perry
- Aliens: Genocide by David Bischoff
- Aliens: Alien Harvest by Robert Sheckley
- Aliens: Rogue by Sandy Schofield
- Aliens: Labyrinth by S. D. Perry
- Aliens: Music of the Spears by Yvonne Navarro