S
- Roméo Sabourin – SOE agent, WW II hero executed by the Nazis
- Giancarlo Scalia – pianist and composer
- Martin St. Louis – NHL hockey player
- Kim St-Pierre – hockey goaltender, Canadian Olympic women's team
- Georges St. Pierre – professional MMA fighter
- Lino Saputo – businessman
- Anne Savage – artist
- Paul Schoeffler – voice actor, actor
- Joseph A. Schwarcz – doctor of chemistry and professor at McGill University and formerly at Vanier College
- Cynthia Scott – Academy Award-winning director
- Frank Scott – scholar, poet, professor, lawyer
- Francis Alexander Caron Scrimger – winner of the Victoria Cross in World War 1
- Marla Shapiro – CTV medical reporter and physician
- William Shatner – actor, best known for playing Captain Kirk in Star Trek
- Douglas Shearer – Oscar winning motion picture sound engineer
- Norma Shearer – Academy Award winning actress
- Madeleine Sherwood – actress, played Mother Superior in The Flying Nun
- Karen Simpson – actress and fashion designer
- Jaspreet Singh – author
- Charles Sirois – telecommunications
- Jeff Skoll – Internet entrepreneur
- Donald Smith – railway executive
- George M. Smith – Lieutenant Governor of Wisconsin
- Larry Smith – former CFL football player, current president of the Montreal Alouettes
- Wonny Song – Classical concert pianist
- Sam Steinberg – supermarket founder
- Ralph M. Steinman – 2011 Nobel laureate in Physiology or Medicine
- George Stephen – banker, railway executive
- Jeff Stinco – lead guitarist of Simple Plan
- P.J. Stock – NHL Hockey player
- Bruny Surin – track and field athlete
- Robert Augustus Sweeney – only African American double recipient of the American Medal of Honor
- Sylvia Sweeney – former basketball player for the Canadian women's national team, TV journalist
- Jack W. Szostak – Nobel Laureate in Physiology or Medicine
Read more about this topic: List Of Montreal Athletes