- Sonic vs. ZonikJonathan Sutherland, Nigel Gross
- South of the BorderRichard Brightfield
- South Pole SabotageSeddon Johnson
- Space Age Terrors!Hilary H. Milton
- Space and BeyondR.A. Montgomery
- Space AssassinAndrew Chapman
- Space FortressEdward Packard
- Space PatrolJulius Goodman
- Space PlagueDavid Orme
- Space RaceRebecca Stefoff
- Space Raiders and the Planet of DoomStephen Mooser
- Space RescueSteve Barlow, Steve Skidmore
- Space Scavenger HuntConnor Hoover
- Space VampireEdward Packard
- Spaced Out!Bobbi J. G. Weiss, David Cody Weiss
- Spawn of DragonspearSteve Perrin
- Spectral StalkersPeter Darvill-Evans
- Spell of the Winter WizardLinda Lowery
- SpellboundRhondi Vilott
- SpellbreakerJonathan Green
- SpellcasterKaty Brown
- Spider-Man vs. the Incredible HulkRichie Chevat
- Spider-Man vs. the Sinister SixRichie Chevat
- SpiedJames Schannep
- Spies of the American RevolutionElizabeth Raum
- Spies of the Civil WarElizabeth Raum
- Spies of World War IMichael Burgan
- Spook ManorDavid Orme
- Spooky ThanksgivingR.A. Montgomery
- SpySteve Barlow, Steve Skidmore
- Spy for CleopatraKatherine Factor
- Spy for George WashingtonDon Hedin
- Stampede!Laban Carrick Hill
- Stanley HotelAllison Lassieur
- Star BastardsHerman S. Skull
- Star Rangers and the SpyBeverly Charette, Jean Blashfield Black
- Star Rangers Meet the Solar RobotBeverly Charette, Mario D. Macari
- Star ReporterTracey West
- Star RiderCarole Carreck
- Star StriderLuke Sharp
- Star System TenopiaRichard Brightfield
- Star Trek: Lower Decks - Warp Your Own WayRyan North
- Star Trek: Phaser FightBarbara Siegel, Scott Siegel
- Star Trek: Voyage to AdventureJohn M. Ford, Michael J. Dodge
- Star Wars: Jedi DawnPaul Cockburn
- Star Wars: The Bounty HunterPaul Cockburn
- Starship DeadfallDean Moodie
- Starship TravellerSteve Jackson
- Starship WarriorStephen Mooser
- Starswirl Do-OverWhitney Ralls
- Statue of Liberty AdventureEllen Kushner
- Stealer of SoulsKeith Martin
- Stealing Nazi Secrets in World War IIElizabeth Raum
- Stepping into the BibleBeverly E. Kostich
- Stock Car ChampionR.A. Montgomery
- Stolen from the StudioLauren Magaziner
- Stop that Witch!Mary Clark
- Storm at the Summit of Mount EverestRyan Jacobson
- Storm of DustNeil Randall
- Storm QuestAndy Prentice