| S/lay w/Me | 2009 | — | — |
| SAGA System | 1996 | TSR | United States |
| Saga-System | 1985 | — | Germany |
| Sagas of the Icelanders | 2013 | self-published work | — |
| Sandman: Map of Halaal | 1985 | — | — |
| Satasupe | 2003 | — | Japan |
| Savage Worlds | 2003 | Pinnacle Entertainment Group | United States |
| Scales | 1994 | — | France |
| Scarlet Heroes | — | — | — |
| Scion | 2007 | White Wolf Publishing | United States |
| Scum and Villainy | 2018 | — | — |
| Second Dawn | 1988 | — | — |
| Sengoku | 1999 | Gold Rush Games | United States |
| Sens Hexalogie | 2010 | self-published work | France |
| Septimus | 2009 | — | — |
| Serenity Role Playing Game | 2005 | Margaret Weis Productions | United States |
| Serial Homicide Unit | 2009 | — | — |
| Shaan | 1996 | Halloween Concept | France |
| Shab-al-Hiri Roach | 2006 | — | — |
| Shadow of the Demon Lord | 2015 | — | — |
| Shadow World | 1987 | Iron Crown Enterprises | United States |
| Shadowdark | 2023 | — | — |
| Shadowrun | 1989 | FASA Corporation, FanPro LLC, Catalyst Game Labs | United States |
| Shadowrun (1st edition) | 1989 | — | — |
| Shadowrun (20th anniversary edition) | 2009 | — | — |
| Shadowrun (2nd edition) | 1992 | — | — |
| Shadowrun (3rd edition) | 1998 | — | — |
| Shadowrun (4th edition) | 2005 | — | — |
| Shadowrun (5th edition) | 2013 | — | — |
| Shadowrun (6th edition) | 2019 | — | — |
| Shadowrun: Anarchy | 2016 | Catalyst Game Labs | United States |
| Shadows of Esteren | 2010 | Agate Editions | France |
| Shatterzone | 1993 | West End Games | United States |
| Shock: Social Science Fiction | 2006 | — | — |
| Shooting the Moon | 2008 | Black and Green Games | United States |
| Sig: City of Blades | 2022 | — | United States |
| Sigil & Shadow | 2021 | Osprey Publishing, Bloomsbury Publishing | — |
| Silhouette Roleplaying Core Rules | 2003 | Dream Pod 9 | Canada |
| Silver Age Sentinels | 2002 | Guardians of Order | Canada |
| Simian Conquest | 1978 | — | — |
| Simple World | 2013 | self-published work | — |
| Simply Roleplaying | 2002 | — | — |
| SimulacreS | 1986 | Casus Belli | France |
| Sine Requie | 2003 | — | — |
| Skulduggery | 2010 | Pelgrane Press | United States |
| Skull & Crossbones | 1980 | Fantasy Games Unlimited | United States |
| SLA Industries | 1993 | Nightfall Games | United Kingdom |
| Sláine: The Roleplaying Game of Celtic Heroes | 2002 | Mongoose Publishing | United States |
| Smallville Roleplaying Game | 2010 | Margaret Weis Productions | United States |
| Solipsist | 2008 | Box Ninja | United States |
| Sombre | — | self-published work | France |
| Songbirds 3e | 2023 | — | United States |
| Sorcerer | 1996 | Adept Press | United States |
| Soth | 2013 | self-published work | — |
| Sovereign Stone | 1999 | Sovereign Press, Inc | United States |
| Space Adventure Cobra | 2013 | — | France |
| Space Gothic | 1993 | — | Germany |
| Space Infantry | 1982 | — | — |
| Space Master | 1985 | Iron Crown Enterprises | United States |
| Space Opera | 1980 | Fantasy Games Unlimited | United States |
| Space Patrol | 1977 | Gamescience | United States |
| Space Quest | 1977 | — | — |
| Space: 1889 | 1988 | Game Designers' Workshop | United States |
| Spaceship Zero | 2002 | Green Ronin Publishing | United States |
| SpaceTime | 1988 | — | — |
| Sphinx | 1984 | — | United Kingdom |
| Sphynx | 2015 | — | France |
| Spione: Story Now in Cold War Berlin | 2007 | Adept Press | United States |
| Spirit of the Century | 2006 | Evil Hat Productions | United States |
| Splicers | 2004 | Palladium Books | United States |
| Splittermond | 2013 | Uhrwerk Verlag | Germany |
| Spycraft | 2002 | Alderac Entertainment Group, Crafty Games | United States |
| Stalker | — | — | Finland |
| Stalking the Night Fantastic | 1983 | Tri Tac Games | United States |
| Star Ace | 1984 | Pacesetter Ltd | United States |
| Star Crossed | 2018 | Bully Pulpit Games | United States |
| Star Drakkar | 2005 | — | France |
| Star Frontiers | 1982 | TSR | United States |
| Star Hero | 2002 | — | — |
| Star Patrol | 1977 | Gamescience | United States |
| Star Rovers | 1981 | — | — |
| Star Trek Adventures | 2017 | — | — |
| Star Trek Roleplaying Game | 2002 | Decipher | United States |
| Star Trek: Adventure Gaming in the Final Frontier | 1978 | Heritage Models | United States |
| Star Trek: Deep Space Nine Role-playing Game | 1999 | Last Unicorn Games | United States |
| Star Trek: The Next Generation Role-playing Game | 1998 | Last Unicorn Games | United States |
| Star Trek: The Original Series Role-playing Game | 1999 | Last Unicorn Games | United States |
| Star Trek: The Role Playing Game | 1982 | FASA Corporation | United States |
| Star Wars Roleplaying Game | 2000 | Wizards of the Coast | United States |
| Star Wars: Edge of the Empire | 2012 | — | United States |
| Star Wars: The Roleplaying Game | 1987 | West End Games | United States |
| Star Wreck Roleplaying Game | 11 August 2006 | — | Finland |
| Starblazer Adventures | 2009 | Cubicle 7 | United Kingdom |
| Starfall | 2015 | — | — |
| Starfaring | 1976 | Flying Buffalo | United States |
| Starfinder Roleplaying Game | 2017 | Paizo Publishing | United States |
| Starfleet Voyages | 1982 | — | — |
| Stargate SG-1 | 2003 | Alderac Entertainment Group | United States |
| Stars Without Number | 2010 | Sine Nomine Publishing | United States |
| Starship Troopers | 2005 | Mongoose Publishing | United States |
| Starships & Spacemen | 1978 | Fantasy Games Unlimited | United States |
| Steal Away Jordan | 2007 | — | — |
| Steissin yö | — | — | Finland |
| Stella Inquisitorus | 1993 | — | France |
| Steve Perrin's Quest Rules | 2008 | — | United States |
| Stormbringer | 1981 | Chaosium | United States |
| Storming the Wizard's Tower | 2008 | Lumpley Games | United States |
| Story Engine | 1999 | — | — |
| Storyboard | 1995 | — | — |
| Storytelling System | 1991 | White Wolf Publishing | United States |
| Street Fighter: The Storytelling Game | 1994 | White Wolf Publishing | United States |
| Striscia | 2018 | Les Livres de l'Ours | France |
| Superhero 2044 | 1977 | Lou Zocchi | United States |
| Supernatural Role Playing Game | 2009 | Margaret Weis Productions | United States |
| Superworld | 1983 | Chaosium | United States |
| Sur les Frontières | 2015 | — | France |
| Swashbuckler | 1998 | — | — |
| Swashbucklers of the 7 Skies | 2009 | Evil Hat Productions | United States |
| Sword and magic | 1987 | — | Finland |
| Sword World 2.0 | — | — | — |
| Sword World RPG | 1989 | Group SNE | Japan |
| Swords & Wizardry | 2008 | — | — |
| Symbaroum | 2015 | Free League Publishing | Sweden |
| System Reference Document | 2000 | — | — |
| Systems Failure | 1999 | Palladium Books | United States |
| S’échapper des Faubourgs | 2013 | self-published work | France |