The Multiverse is the name given to the ever growing number of alternate dimensions. Apparently, it is required to cross the Omnizone to reach all the dimensions. In the series and novels, multiple alternate dimensions and timelines are shown to exist. Also, it has been stated that alternate realities are also created through dreams and hallucinations, which might mean that there are universes based on video games.
- Red Dwarf's universe and believed to be the "prime" dimension where every alternate universe spawned from.
- A dimension where female/male relations are reversed, home to Deb Lister, Arlene Rimmer, Hilly, and The Dog. (RD: Parallel Universe)
- HtraE at a point in the future where time runs backwards. RD: Backwards
- Ace Rimmer's home dimension (RD: Dimension Jump).
- Dimension 165, where the original Ace died (RD: Stoke Me a Clipper).
- Princess Bonjella's dimension, A dimension where the Nazis won WW2, and it is also hinted crocodiles are kept as pets (RD: Stoke Me a Clipper).
- Dimension 24, where the Ace before the Rimmer in Red Dwarf 's dimension went to have his hair done (RD: Stoke Me a Clipper).
- Kristine Kochanski's dimension, where she found Frankenstein and got caught instead of Lister. (RD: Ouroboros)
- A dimension created by the crew's original hallucination in "Back to Reality" where there is a fascist state and "Red Dwarf" is a total immersion video game (RD: Back To Reality).
- A dimension created by the crew's group hallucination in "Back to Earth", where everyone there believes they're the real ones and "Red Dwarf" is just a television show. (RD: Back To Earth)
- A dimension formed from anomalies in two different dimensions after the future Dwarfers killed their past selves (explained by Lister) and coexists with the prime dimension. (RD: Tikka To Ride)
- A Mirror Universe, where everything was the opposite of the original dimension. (RD: Only The Good...)
- Twentica was created by the influence of the time-traveling Expanoids. In order to stop humans from ever becoming a threat, all technology was prohibited on Twentica.
- A Universe where Lister is a 'posh gentleman' who smuggled a rat onboard Red Dwarf instead of a cat, resulting in a race of giant rats (Rattus sapiens) such as The Rat occupying every deck on the ship (RD: Skipper)
- A Universe filled with multiple Listers (RD: Skipper)
- A Universe to which Rimmer skipped where the crew were still alive and the Radiation leak was just about to happen. He was already the ships hologram in this universe.(Cause of death is unknown) and Captain Hollister died in a escape pod that jammed when he tried to use it. (RD: Skipper)
- A Universe where Lister didn't get put into stasis and spotted the faulty drive plate which lead to him getting promoted and working his way up to become the Captain of the ship.In this universe, Rimmer is also a married navigation officer with four sons. (RD: Skipper)
- A Universe where Rimmer is the ship's computer. (RD: Skipper)
- A Universe where Red Dwarf is blue and is likely not called Red Dwarf. (RD: Skipper)
- The home dimension of the Ace Rimmer that recruited the Rimmer from Red Dwarf's dimension, where Rimmer stole the Time Drive and left the others for dead. Before he was recruited by the Ace before him, he ended up in Napoleonic times (at a point when conscription was introduced). (RD: Stoke Me A Clipper [deleted scene])
- Universe 3 located in the Omnizone, where time runs backwards. (Backwards)
- A universe where Lister and the Cat died playing Better Than Life. (Backwards)
- A universe inhabited by GELFs from the Mayflower. (Last Human)
- The dimension where the sociopathic Lister came from (Last Human)
- The non-canon Red Christmas universe. (Red Christmas)