Science Fiction roleplaying games usually focus on the future, and usually use technology as the source of wonder, where a Fantasy game would use magic. Aliens, spaceships, psionics, laser blasts, and other planets all have their place here, though not all games will use all of these. The first Science Fiction roleplaying game (the first roleplaying game at all that was not a medieval fantasy) was GDW's Traveller.
Sites for a homemade "free" roleplaying systems should be submitted to the Free Systems subcategory.
2300 AD (originally Traveller: 2300) is a "hard science" game of exploration and warfare set among the space colonies of the 24th Century. Originally published by Games Designers Workshop, 2300 AD is currently owned by Far Future Enterprises.
Published by Wizards of the Coast, the Alternity system is adaptable to a variety of science fiction genres. Alternity's rules were influenced by prior TSR/WOTC games, Dungeons and Dragons and Gamma World.
A science fiction game published in 1997 by Chameleon Eclectic Entertainment, and based on the television series Babylon 5.
Science fiction game published by SSDC, wherein players assume the role of mercenaries hired by megacorporations to fight alien threats.
Published by Biohazard Games in 1997, Blue Planet is a dark science fiction game set on the aquatic planet Poseidon in A.D. 2199.
Science fiction game about time-traveling "spanners", published by Aetherco.

This category does not list sites related to Subspace Continuum.

Cyberpunk 2020, The Roleplaying Game of the Dark Future, is the first and most successful cyberpunk-genre roleplaying game, originally published by R. Talsorian in 1988 under the title Cyberpunk.
Post-apocalyptic game published by Anarchy inK, portraying the rebuilding of civilization after a 21st-century nuclear war.
Fading Suns is a futuristic / medieval setting where the three main powers of the Nobility, the Church, and the Merchant League struggle against each other and outside forces. It is a realm of high-tech spaceships, knights, weird aliens, holy warriors, strange worlds, and many other things all at once. Fading Suns has often been compared to the likes of the Hyperion, Dune, Babylon 5,and even Star Wars. Step inside and raise your noble house's banner against the barbarians and the Darkness between the stars, and may the fading suns light your way...
Non-commercial tabletop roleplaying games based in science fiction (defined for these purposes as rules or settings that use science and technology as central themes, rather than the mysticism that defines the Fantasy and Horror categories.
This category is for pen-and-paper roleplaying games. Online, chat-based, and freeform games should be submitted to one of the subcategories of Games/Internet/Chat.

Games that are sold for money instead of given away must be submitted to the related category Games/Roleplaying/Genres/Science_Fiction.

TSR's post-apocalyptic science fantasy, set in a 24th Century world populated by insane robots, intelligent animals, and freakish mutants. Loosely derived from the earlier game Metamophosis Alpha, Gamma World had four separate editions before going out of print.
Dirt Merchant Games' "adult" comedic science fiction roleplaying game set on Hol, the combination garbage dump and prison planet of the galaxy-spanning Confederation of Worlds.
This category is for sites about traditional role-playing games based in the world of the Matrix series, which includes a trilogy of films, nine anime episodes, and two computer games. The Matrix is a computer-generated virtual reality simulation built by an artificial intelligence to enslave humans while using their energy for its own purposes.
Please submit only sites with content relating to traditional [table-top] role-playing games based in the world of the Matrix series.

Please do not submit sites that are under construction.

A science-fiction roleplaying game set in FASA's BattleTech universe.
Post-apocalyptic system published in 1980 by Timeline, Ltd. The eponymous Morrow Project is a secret group of cryogenically-frozen 20th-century scientists and soldiers revived after a nuclear war to rebuild American civilization.
Science-fiction roleplaying game published by 6-0 Games.
West End Games' post-apocalyptic role-playing game of dark humor, Paranoia features a Big Brother-esque computer, mutants, secret societies, and high character mortality rates. In 2004, a couple of the original designers bought back the rights to it and remade the game into a new edition called Paranoia XP, published by Mongoose Publishing.
Reich Star is an out-of-print science fiction roleplaying game published by Creative Encounters. The game takes place in an alternate future in which the Axis powers won World War II.
Palladium Books' combat-heavy system based on the animated series of the same name.
Shadowrun is a near-future roleplaying game, set in the sixth age of humanity, when mankind has mutated and magic has returned to the earth. A great RPG from FASA Corporation, with heaps of support online.
Skyrealms of Jorune is a role playing game set in a unique alien world. Originally sold in the 1980s and currently out of active print, the game continues to have a dedicated following worldwide.
Please submit only sites dealing with the Skyrealms of Jorune gaming system. Articles for sale should be listed under shopping. Sites containing copyright infringement will not be listed. Sites in languages other than English will be listed in the /world directory.
Nightfall Games' system of "futuristic urban horror". Player characters are operatives of the eponymous SLA Industries, a galaxy-ruling megacorporation run by the immortal Mr. Slayer.
Iron Crown Enterprises' 1985 science-fiction game based on its Rolemaster system. Originally titled Space Master, the game has most recently been re-released as Spacemaster: Privateers.
Developed by Frank Chadwick and originally published by Game Designers' Workshop, this game inspired by Victorian science fiction game is currently published by Heliograph, Inc.
Designed by Edward E. Simbalist, A. Mark Ratner, and Phil McGregor, this science-fiction system was published by Fantasy Games Unlimited in 1981.
Star Frontiers was a science-fiction roleplaying game published by TSR, Inc. in the 1980s. It is currently out of print.
Beginning in 1998, Last Unicorn Games (a subsidiary of Wizards of the Coast) actually produced four related games based on the famous science-fiction television series: Star Trek: The Next Generation, Star Trek: Deep Space Nine, Star Trek: The Original Series, and Star Trek: The Expanded Universe.
Roleplaying in the World of Star Wars.
Please submit sites about the West End Games version to the Classic, and sites about Star Wars d20 to the d20 System category. Only sites that have much content for both systems are accepted directly in this category.
In this unusual science fiction game published by Palladium Books, player characters are Y2K survivalists who must band together to save America from insectoid aliens who invaded the Earth on January 1, 2000.
A science-fiction game of time-travelers published by Blacksburg Tactical Research Center.
The first, largest and best Science Fiction Role Playing Game: Traveller. See milieu non-specific sites here, or click on your favorite version to see specialized sites.
Sites whose main thrust covers, supports or records games or ongoing campaigns. Most of these have supporting character, technology, encounter and location information that may be useful to parties outside of the gaming group involved.
Science fiction game published by White Wolf Publishing (sharing many basic Storyteller mechanics with the World of Darkness games) set in a 22nd-century world under assault from the Aberrants, vengeful descendants of superhumans exiled from the planet a century earlier. Player characters are Psions, brought together by the Aeon Trinity to defend the Earth.
Please submit only sites dealing specifically with Aberrant in this category. Sites which deal with the Trinity Universe in general should be submitted one level up.
Near-future game produced by Game Designers' Workshop (GDW) in 1984, Twilight: 2000 portrays the adventures of American soldiers stranded in Europe after World War III. The rules system developed for T2K later became GDW's "house system", used for several other games.