| Cadillacs and Dinosaurs | 1990 | — | — |
| Cadwallon | 2006 | — | — |
| Cairn | 2020 | — | — |
| Call of Cthulhu | 1981 | Chaosium | United States |
| Call of Cthulhu (1st ed.) | 1981 | Chaosium | United States |
| Call of Cthulhu (2nd edition) | 1983 | — | — |
| Call of Cthulhu (3rd edition) | 1986 | — | — |
| Call of Cthulhu (4th edition) | 1989 | — | — |
| Call of Cthulhu (5.5 edition) | 1998 | — | — |
| Call of Cthulhu (5th ed.) | 1992 | Chaosium | United States |
| Call of Cthulhu (6th ed.) | 2004 | Chaosium | United States |
| Call of Cthulhu (7th edition) | 2014 | — | — |
| Candela Obscura | 14 November 2023 | — | — |
| Capes | 2005 | — | — |
| Capes, Cowls & Villains Foul | 2010 | — | — |
| Capharnaüm | 2007 | Le Septième Cercle | France |
| Capitaine vaudou | 1991 | Casus Belli | France |
| Capitan Alatriste | 2002 | — | Spain |
| Carcosa | 2008 | — | United States |
| Carry: A Game about War | 2006 | — | — |
| Cartoon Action Hour | 2002 | Spectrum Games | United States |
| Cassiopean Empire | 1982 | — | — |
| Castle Falkenstein | 1994 | R. Talsorian Games | United States |
| Castles & Crusades | 2004 | Troll Lord Games | United States |
| Cats of Catthulhu | — | — | — |
| Cendres | 2002 | — | France |
| Cepheus Engine | 2014 | — | — |
| Challengers | 1985 | — | — |
| Champions | 1981 | Hero Games | United States |
| Champions (1st edition) | 1981 | — | — |
| Champions (2nd edition) | 1982 | — | — |
| Champions (3rd edition) | 1984 | — | — |
| Champions (4th edition) | 1989 | — | — |
| Champions (5th edition) | 2002 | — | — |
| Champions (6th edition) | 2010 | — | — |
| Champions: New Millennium | 1997 | — | — |
| Changeling: The Dreaming | 1995 | White Wolf Publishing | United States |
| Changeling: The Lost | 2007 | White Wolf Publishing | United States |
| Children of the Sun | 2002 | — | — |
| Chill | 1984 | Pacesetter Ltd | United States |
| Chimères | 1994 | Multisim | France |
| Chivalry & Sorcery | 1977 | Fantasy Games Unlimited | United States |
| Chivalry & Sorcery (1st edition) | 1977 | — | — |
| Chivalry & Sorcery (2nd edition) | 1983 | — | — |
| Chivalry & Sorcery (3rd edition) | 1996 | — | — |
| Chivalry & Sorcery (5th edition) | 2020 | — | — |
| Chivalry & Sorcery (Essence v1.1) | 2011 | — | — |
| Chivalry & Sorcery (light edition) | 1999 | — | — |
| Chivalry & Sorcery (Rebirth edition) | 2000 | — | — |
| Chouans et Vendéens | 1989 | — | France |
| Chronica Feudalis | 2009 | — | — |
| Chronicles of Ramlar | 2006 | — | — |
| Chuubo's Marvelous Wish Granting Engine | 2014 | — | — |
| Circle of Hands | 2015 | — | — |
| Cirkus | 2005 | — | — |
| City of Mist | October 2017 | Son of Oak Game Studio | Israel |
| CJ Carella's WitchCraft | 1999 | Eden Studios, Inc. | United States |
| Classic Traveller | 1977 | Game Designers' Workshop | United States |
| Cloak of Steel | 2004 | — | — |
| Cold City | 2007 | — | — |
| Colonial Gothic | 2007 | — | — |
| Colostle | 2022 | — | — |
| Comandos de Guerra | 1994 | Ediciones Sombra | Spain |
| Commando | 1979 | — | — |
| Conan Role-Playing Game | 1985 | TSR | United States |
| Conan: The Roleplaying Game | 2004 | Mongoose Publishing | United States |
| Conspiracy of Shadows | 2004 | — | — |
| Conspiracy X | 1996 | Steve Jackson Games | United States |
| Contenders | 2007 | — | — |
| Continuum | 1999 | — | United States |
| COPS | 2003 | Oriflam | France |
| CORE Command | 2003 | Dream Pod 9 | Canada |
| Coriolis | 2008 | — | Sweden |
| Corporation | 2006 | — | United States |
| Corporia | 2014 | — | — |
| CORPS | 1990 | Blacksburg Tactical Research Center | United States |
| Cortex Plus | 2010 | Margaret Weis Productions | United States |
| Cortex System | 2005 | Margaret Weis Productions | United States |
| Cosmic Patrol | 2011 | Catalyst Game Labs | United States |
| Covenant | 2006 | — | — |
| Coyote & Crow | 2021 | — | — |
| Creeks and Crawdads | 1986 | — | — |
| Crime Fighter | 1988 | — | — |
| Crimefighters | 1981 | — | — |
| Crimes | 2006 | — | — |
| Crystalicum | 2006 | — | Poland |
| Crystania RPG | — | — | Japan |
| Cthulhu Confidential | May 2017 | Pelgrane Press | United States |
| Cthulhu Dark | 2010 | — | — |
| CthulhuTech | 2007 | Mongoose Publishing | United States |
| Cue System | — | Catalyst Game Labs | — |
| Cutthroat: The Shadow Wars | 1988 | — | — |
| Cyber Age | 1990 | Jeux Descartes | France |
| Cybergeneration | 1993 | R. Talsorian Games | United States |
| Cyberpunk | 1988 | R. Talsorian Games | United States |
| Cyberpunk 2020 | 1990 | R. Talsorian Games | United States |
| Cyberpunk 3.0 | 2005 | R. Talsorian Games | United States |
| Cyberpunk RED | 2020 | R. Talsorian Games | — |
| Cyberpunk RPG | — | — | — |
| Cyberspace | 1989 | Jeux Descartes | France |
| Cyborg Commando | 1987 | — | — |
| Cypher System | — | Monte Cook Games | — |