| Cameron Saaiman | MSP | 3-3-0 | South Africa | Apr 26, 2025 |
| Pat Sabatini | | 9-2-0 | United States | May 9, 2026 |
| Amir Sadollah (inactive) | | 6-5-0 | United States | Sep 20, 2014 |
| Nazim Sadykhov | Black Wolf | 4-2-1 | Russia | Jun 27, 2026 |
| Frankie Saenz | | 5-5-0 | United States | Aug 1, 2020 |
| Saparbeg Safarov (inactive) | | 1-3-0 | Russia | Mar 7, 2020 |
| Tarec Saffiedine (inactive) | Sponge | 2-4-0 | Belgium | Jun 17, 2017 |
| Jason Saggo (inactive) | | 3-3-0 | Canada | Sep 16, 2017 |
| Kiru Sahota (inactive) | | 0-1-0 | Unknown | Nov 23, 2024 |
| Muhammad Saidov | Kubik | 1-0-0 | Unknown | Jul 25, 2026 |
| Lukasz Sajewski (inactive) | Wookie | 0-3-0 | Poland | Oct 8, 2016 |
| Augusto Sakai (inactive) | | 5-4-0 | Brazil | Feb 25, 2023 |
| Alessio Sakara (inactive) | Legionarius | 6-8-0 (1 NC) | United States | Oct 26, 2013 |
| Gokhan Saki (inactive) | The Rebel | 1-1-0 | Türkiye | Jul 7, 2018 |
| Kazushi Sakuraba (inactive) | The Gracie Hunter | 1-0-0 (1 NC) | Unknown | Dec 21, 1997 |
| Hayato Sakurai (inactive) | Mach | 0-1-0 | United States | Mar 22, 2002 |
| Justin Salas (inactive) | J-Bomb | 3-4-0 | United States | Mar 5, 2016 |
| Ivan Salaverry (inactive) | | 3-4-0 | Canada | May 24, 2008 |
| Roman Salazar (inactive) | El Gallito | 0-2-0 (1 NC) | United States | Aug 8, 2015 |
| Luis Saldana (inactive) | | 2-1-1 | United States | Aug 20, 2022 |
| Muslim Salikhov | King of Kung Fu | 9-6-0 | Russia | Sep 12, 2026 |
| Quillan Salkilld | | 6-0-0 | Australia | Aug 8, 2026 |
| Boston Salmon (inactive) | Boom Boom | 0-2-0 | United States | Oct 18, 2019 |
| Sean Salmon (inactive) | | 0-2-0 | United States | May 26, 2007 |
| John Salter (inactive) | | 1-2-0 | United States | Aug 28, 2010 |
| Vinicius Salvador (inactive) | | 0-3-0 | Brazil | May 18, 2024 |
| Josh Samman (inactive) | Anqa | 3-2-0 | United States | Jul 13, 2016 |
| Josh Sampo (inactive) | The Gremlin | 1-3-0 | United States | May 23, 2015 |
| Andrew Sanchez (inactive) | El Dirte | 5-5-0 | United States | Oct 16, 2021 |
| Diego Sanchez (inactive) | Nightmare | 19-13-0 | United States | Sep 26, 2020 |
| Eddie Sanchez (inactive) | The Manic Hispanic | 3-3-0 | United States | Dec 10, 2008 |
| Joby Sanchez (inactive) | | 1-4-0 | United States | Nov 10, 2018 |
| Julian Sanchez (inactive) | | 0-1-0 | Unknown | Sep 20, 1996 |
| Robert Sanchez (inactive) | Littlefury | 1-2-0 | United States | Sep 8, 2018 |
| Jerrod Sanders (inactive) | J-Reazie | 1-2-0 (1 NC) | United States | Jul 7, 2016 |
| Jesse Sanders (inactive) | | 0-1-0 | United States | Apr 1, 2009 |
| Luke Sanders (inactive) | Cool Hand | 3-5-0 | Unknown | May 1, 2021 |
| Cory Sandhagen | | 11-6-0 | United States | Jul 11, 2026 |
| Hector Sandoval (inactive) | Kid Alex | 2-2-0 | Mexico | Aug 5, 2017 |
| Joseph Sandoval (inactive) | | 0-2-0 | United States | Jan 20, 2012 |
| Chris Sanford (inactive) | | 0-1-0 | United States | Apr 9, 2005 |
| Roldan Sangcha'an (inactive) | The Executioner | 0-2-0 | Unknown | May 16, 2015 |
| Martin Sano (inactive) | Spartan | 0-1-0 | United States | Sep 25, 2021 |
| Duda Santana (inactive) | Cowboyzinha | 0-1-0 | Brazil | Jun 1, 2019 |
| Hector Santiago | | 1-0-0 | Brazil | Aug 29, 2026 |
| Jorge Santiago (inactive) | The Sandman | 1-5-0 | Brazil | Feb 16, 2013 |
| Mike Santiago (inactive) | | 0-3-0 | United States | Jun 9, 2018 |
| Adriano Santos (inactive) | | 0-1-0 | Unknown | Oct 16, 1998 |
| Anderson Dos Santos (inactive) | Berinja | 1-3-0 | Brazil | Aug 7, 2021 |
| Antonio Dos Santos (inactive) | Junior Alpha | 0-2-0 | Brazil | Jun 20, 2015 |
| Bruno Santos (inactive) | Carioca | 1-2-0 | Brazil | Oct 4, 2014 |
| Daniel Santos | Willycat | 4-2-0 | Brazil | May 16, 2026 |
| Djorden Santos | Shakur | 1-3-0 | Brazil | Sep 12, 2026 |
| Elizeu Zaleski dos Santos (inactive) | Capoeira | 11-6-1 | Brazil | Aug 2, 2025 |
| Felipe dos Santos (inactive) | Lipe Detona | 1-3-0 | Brazil | Mar 22, 2025 |
| Gabriel Santos | Mosquitinho | 2-2-0 | Brazil | Feb 8, 2025 |
| Iliarde Santos (inactive) | | 0-3-0 | Brazil | Oct 9, 2013 |
| Junior Dos Santos (inactive) | Cigano | 15-8-0 | Unknown | Dec 12, 2020 |
| Leonardo Santos (inactive) | | 7-3-1 | Brazil | Aug 20, 2022 |
| Luana Santos | | 6-1-0 | Brazil | Jun 20, 2026 |
| Mairon Santos | The Legend | 4-0-0 | Unknown | Dec 6, 2025 |
| Paulo Santos (inactive) | | 0-1-0 | Brazil | Oct 16, 1998 |
| Rayanne dos Santos | | 0-3-0 | Brazil | May 31, 2025 |
| Taila Santos | | 4-3-0 | Brazil | Aug 26, 2023 |
| Thiago Santos (inactive) | Marreta | 14-10-0 | Brazil | Aug 6, 2022 |
| Yana Santos | | 7-5-0 | Russia | Oct 4, 2025 |
| Nick Sanzo (inactive) | | 1-1-0 | Unknown | Feb 7, 1997 |
| Daniel Sarafian (inactive) | | 2-4-0 | Unknown | Feb 21, 2016 |
| Jeka Saragih (inactive) | | 1-3-0 | Indonesia | Jun 7, 2025 |
| Diego Saraiva (inactive) | The Octopus | 0-3-0 | Brazil | Sep 22, 2007 |
| Gokhan Saricam | | 1-0-0 | Belgium | Apr 18, 2026 |
| Yuki Sasaki (inactive) | | 0-1-0 | Japan | Aug 17, 2006 |
| Yuta Sasaki (inactive) | Ulka | 4-5-0 | Unknown | Nov 17, 2018 |
| Paul Sass (inactive) | | 3-2-0 | United Kingdom | Feb 16, 2013 |
| Takashi Sato (inactive) | Ten | 2-5-0 | Japan | May 20, 2023 |
| Takenori Sato (inactive) | | 0-2-0 | Japan | Sep 20, 2014 |
| Uran Satybaldiev | Gorilla | 1-1-0 | Kyrgyzstan | Aug 23, 2025 |
| Ben Saunders (inactive) | Killa B | 9-10-0 | United States | Dec 14, 2019 |
| Chris Saunders (inactive) | The So Cal Kid | 0-1-0 | Unknown | Jun 1, 2012 |
| Townsend Saunders (inactive) | | 0-2-0 | Unknown | Jan 8, 1999 |
| Matt Sayles (inactive) | | 1-3-0 | United States | Dec 18, 2021 |
| Mark Scanlon (inactive) | | 0-1-0 | United Kingdom | Nov 13, 2010 |
| Eric Schafer (inactive) | Red | 3-6-0 | United States | Jan 20, 2012 |
| Kerry Schall (inactive) | Meat Truck | 0-1-0 | United States | Nov 5, 2005 |
| Brendan Schaub (inactive) | Big Brown | 6-5-0 | United States | Dec 6, 2014 |
| Fabiano Scherner (inactive) | Pegaleve | 0-2-0 | Brazil | May 27, 2006 |
| Samy Schiavo (inactive) | | 0-2-0 | France | Oct 18, 2008 |
| Pat Schilling (inactive) | Thrilling | 0-2-0 | United States | Jun 1, 2012 |
| Semmy Schilt (inactive) | Hightower | 1-1-0 | Netherlands | Jun 29, 2001 |
| Ollie Schmid | The Hungarian Stallion | 0-1-0 | United States | May 2, 2026 |
| Matt Schnell (inactive) | Danger | 7-9-0 (1 NC) | United States | Jun 6, 2026 |
| Alex Schoenauer (inactive) | | 0-1-0 | Argentina | Apr 9, 2005 |
| Darrill Schoonover (inactive) | The Boss | 0-1-0 | United States | Dec 5, 2009 |
| Nate Schroeder (inactive) | | 0-1-0 | Unknown | Jun 9, 2000 |
| Mark Schultz (inactive) | | 1-0-0 | United States | May 17, 1996 |
| Wes Schultz | Party Time | 1-2-0 | United States | Aug 22, 2026 |
| Justin Scoggins (inactive) | | 4-5-0 | United States | Jul 14, 2018 |
| Brad Scott (inactive) | Bear | 3-5-0 | United Kingdom | May 27, 2018 |
| Zachary Scroggin (inactive) | | 0-1-0 | United States | Nov 9, 2024 |
| Neil Seery (inactive) | 2Tap | 3-4-0 | Ireland | Jul 16, 2017 |
| Stefan Sekulic (inactive) | | 0-2-0 | Serbia | Apr 24, 2021 |
| Pete Sell (inactive) | Drago | 2-5-0 | United States | Mar 7, 2009 |
| Matthew Semelsberger (inactive) | Semi The Jedi | 5-6-0 | United States | Nov 9, 2024 |
| Andrei Semenov (inactive) | | 1-1-0 | Russia | May 10, 2002 |
| Mackens Semerzier (inactive) | Da Menace | 1-1-0 (1 NC) | United States | Mar 2, 2012 |
| Ivan Serati (inactive) | | 0-1-0 | Italy | Jan 17, 2009 |
| Matt Serra (inactive) | The Terra | 7-7-0 | United States | Sep 25, 2010 |
| Nick Serra (inactive) | The Mad Monkey | 0-1-0 | United States | Jun 22, 2002 |
| Adrian Serrano (inactive) | | 0-1-0 | United States | Jun 9, 2000 |
| Fredy Serrano (inactive) | El Profe | 2-2-0 | Colombia | Dec 17, 2016 |
| Igor Severino | | 0-1-0 | Brazil | Mar 23, 2024 |
| Dan Severn (inactive) | The Beast | 9-4-0 | United States | Sep 22, 2000 |
| Rosi Sexton (inactive) | The Surgeon | 0-2-0 | France | Oct 26, 2013 |
| Rodrigo Sezinando | | 0-1-0 | Brazil | Sep 13, 2025 |
| Edmen Shahbazyan | The Golden Boy | 10-6-0 | United States | Sep 19, 2026 |
| Leon Shahbazyan | S.O.G. | 0-1-0 | United States | Jun 20, 2026 |
| Don Shainis (inactive) | Shameless | 0-2-0 | United States | Feb 11, 2023 |
| Liliya Shakirova (inactive) | | 0-1-0 | Unknown | Oct 24, 2020 |
| Kamal Shalorus (inactive) | Prince of Persia | 0-3-0 | Iran | May 15, 2012 |
| Frank Shamrock (inactive) | | 5-0-0 | United States | Sep 24, 1999 |
| Ken Shamrock (inactive) | The World's Most Dangerous Man | 6-5-2 | United States | Oct 10, 2006 |
| Sean Sharaf | The Smoke | 1-2-0 | United States | Sep 19, 2026 |
| Eric Shelton (inactive) | Showtime | 2-4-0 | United States | Mar 23, 2019 |
| Sean Sherk (inactive) | The Muscle Shark | 8-4-0 | United States | Sep 25, 2010 |
| Chase Sherman (inactive) | The Vanilla Gorilla | 4-11-0 | United States | May 13, 2023 |
| Antonina Shevchenko (inactive) | La Pantera | 4-4-0 | Kyrgyzstan | Jul 9, 2022 |
| Valentina Shevchenko | Bullet | 15-3-1 | Kyrgyzstan | Nov 15, 2025 |
| Jake Shields (inactive) | | 4-3-0 (1 NC) | United States | Mar 15, 2014 |
| Shunichi Shimizu (inactive) | | 0-1-0 | Japan | Jan 4, 2014 |
| Wade Shipp (inactive) | The Nightmare | 0-1-0 | United States | Apr 2, 2004 |
| Josh Shockley (inactive) | | 0-2-0 | United States | Feb 22, 2015 |
| Josh Shockman (inactive) | The War Hammer | 0-1-0 | Unknown | Nov 18, 2006 |
| Liudvik Sholinian (inactive) | Palmeyros | 0-2-0 | Armenia | Nov 5, 2022 |
| Jack Shore (inactive) | Tank | 6-3-0 | United Kingdom | Nov 2, 2024 |
| Sam Sicilia (inactive) | | 5-7-0 | United States | Feb 19, 2017 |
| Serhiy Sidey | | 2-1-0 | Ukraine | May 3, 2025 |
| Steven Siler (inactive) | Super | 5-4-0 | United States | Jul 26, 2014 |
| Alex Da Silva (inactive) | Leko | 1-3-0 | Brazil | Jun 4, 2022 |
| Anderson Silva (inactive) | The Spider | 17-7-0 (1 NC) | Brazil | Oct 31, 2020 |
| Antonio Silva (inactive) | Bigfoot | 3-7-1 | Brazil | Sep 24, 2016 |
| Ariane da Silva (inactive) | Queen of Violence | 6-8-0 | Brazil | Jun 7, 2025 |
| Assuerio Silva (inactive) | | 0-3-0 | Brazil | Apr 21, 2007 |
| Bruno Silva | Bulldog | 5-6-0 (1 NC) | Brazil | Jun 6, 2026 |
| Bruno Silva | Blindado | 4-7-0 | Unknown | May 10, 2025 |
| Claudio Silva (inactive) | Hannibal | 5-3-0 | Brazil | Jul 23, 2022 |
| Danny Silva | El Puma | 3-1-0 | United States | Mar 21, 2026 |
| Erick Silva (inactive) | | 7-8-0 | Brazil | Dec 16, 2017 |
| Erik Silva (inactive) | The King | 0-3-0 | Venezuela | Feb 28, 2026 |
| Felipe Silva (inactive) | | 1-2-0 | Brazil | May 19, 2018 |
| Gabriel Silva (inactive) | | 0-2-0 | Brazil | Feb 29, 2020 |
| Henrique da Silva | Frankenstein | 2-4-0 | Brazil | Sep 22, 2017 |
| Jay Silva (inactive) | | 0-2-0 | Brazil | Jan 11, 2010 |
| Jean Silva | Lord | 7-1-0 | Brazil | Sep 12, 2026 |
| Joaquim Silva | Netto BJJ | 7-5-0 | Brazil | Sep 13, 2025 |
| Karine Silva | Killer | 5-3-0 | Brazil | Apr 18, 2026 |
| Leandro Silva (inactive) | Buscape | 3-4-0 (1 NC) | Brazil | Sep 3, 2016 |
| Mayra Bueno Silva (inactive) | Sheetara | 5-7-1 (1 NC) | Brazil | Apr 25, 2026 |
| Natalia Silva | | 9-0-0 | Brazil | Oct 3, 2026 |
| Thiago Silva (inactive) | | 7-3-0 (2 NC) | Brazil | Oct 9, 2013 |
| Tiago dos Santos e Silva (inactive) | Trator | 2-2-0 | Unknown | Dec 9, 2016 |
| Wagner Silva (inactive) | Wagnao | 0-2-0 | Brazil | Nov 8, 2014 |
| Wanderlei Silva (inactive) | The Axe Murderer | 5-7-0 | Brazil | Mar 2, 2013 |
| Marcus Silveira (inactive) | Conan | 0-1-0 (1 NC) | Unknown | Dec 21, 1997 |
| Elias Silverio (inactive) | Xuxu | 3-2-0 | United States | Aug 23, 2015 |
| Jamey Simmons (inactive) | The Afro Samurai | 0-2-0 | United States | Aug 7, 2021 |
| Ricky Simon | | 10-7-1 | United States | Sep 26, 2026 |
| Aaron Simpson (inactive) | A-Train | 7-4-0 | United States | Oct 5, 2012 |
| Tony Sims (inactive) | | 1-2-0 | United States | Jan 2, 2016 |
| Wes Sims (inactive) | The Project | 0-3-0 | United States | Apr 2, 2004 |
| Lodune Sincaid (inactive) | | 0-1-0 | United States | Apr 9, 2005 |
| Rory Singer (inactive) | Outburst | 2-2-0 | United States | Jun 16, 2007 |
| Elvis Sinosic (inactive) | The King of Rock n' Rumble | 1-6-0 | Australia | Apr 21, 2007 |
| Fabia Sintes | El Potro Menorquin | 1-0-0 | Spain | Sep 5, 2026 |
| Jamie Siraj | The Gremlin | 0-1-0 | Canada | Apr 18, 2026 |
| Dennis Siver (inactive) | | 12-8-0 (1 NC) | Russia | Jun 25, 2017 |
| Chas Skelly (inactive) | The Scrapper | 8-3-0 (1 NC) | United States | Feb 19, 2022 |
| Joe Slick (inactive) | | 1-1-0 | United States | Apr 14, 2000 |
| Anthony Smith (inactive) | Lionheart | 13-12-0 | United States | Apr 26, 2025 |
| Braxton Smith (inactive) | The Beautiful Monster | 0-1-0 | United States | May 6, 2023 |
| Cole Smith (inactive) | The Cole Train | 1-2-0 | Canada | Sep 5, 2020 |
| Colton Smith (inactive) | | 1-3-0 | United States | Jun 28, 2014 |
| Devonte Smith (inactive) | King Kage | 3-3-0 | United States | Mar 5, 2022 |
| Elijah Smith | Swift | 3-0-0 | United States | Mar 14, 2026 |
| Gilbert Smith (inactive) | | 0-1-0 | United States | Apr 13, 2013 |
| Jacobe Smith | Cobe | 4-0-0 | United States | Oct 3, 2026 |
| Leslie Smith (inactive) | The Peacemaker | 4-3-0 | United States | Jul 16, 2017 |
| Maurice Smith (inactive) | | 4-3-0 | United States | Nov 17, 2000 |
| Patrick Smith (inactive) | | 4-1-0 | United States | Jul 14, 1995 |
| Scott Smith (inactive) | Hands of Steel | 1-3-0 | United States | Jun 16, 2007 |
| Trevor Smith (inactive) | Hot Sauce | 5-7-0 | Unknown | Dec 7, 2019 |
| Dmitrii Smoliakov (inactive) | The Lifeguard | 0-3-0 | Belarus | Apr 27, 2019 |
| Louis Smolka (inactive) | Da Last Samurai | 8-9-0 | United States | May 14, 2022 |
| Cameron Smotherman (inactive) | The Baby-Faced Killa | 1-3-0 | United States | May 30, 2026 |
| Richie Smullen (inactive) | | 0-1-0 | Ireland | Jul 6, 2018 |
| Peter Sobotta (inactive) | | 4-6-0 | Poland | Jul 25, 2020 |
| Renato Sobral (inactive) | Babalu | 6-4-0 | Brazil | Aug 25, 2007 |
| Rameau Thierry Sokoudjou (inactive) | The African Assassin | 1-2-0 | Cameroon | Oct 18, 2008 |
| Axel Sola | | 3-1-0 | France | Sep 5, 2026 |
| Roberto Soldic | Robocop | 1-0-0 | Bosnia & Herzegovina | Oct 3, 2026 |
| Joe Solecki (inactive) | | 5-4-0 | United States | Jan 11, 2025 |
| Jin Soo Son (inactive) | | 0-2-0 | South Korea | Jul 20, 2019 |
| Joe Son (inactive) | | 0-1-0 | United States | Dec 16, 1994 |
| Chael Sonnen (inactive) | | 7-7-0 | Unknown | Nov 16, 2013 |
| Benardo Sopaj | Lion King | 2-1-0 | Albania | May 16, 2026 |
| Punahele Soriano | Puna | 7-5-0 | United States | Sep 5, 2026 |
| Sean Soriano (inactive) | | 0-5-0 | United States | Nov 20, 2021 |
| Hecher Sosa | Guanche Warrior | 1-0-0 | Spain | Mar 14, 2026 |
| Dmitry Sosnovskiy (inactive) | Wicked Machine | 1-0-0 | Russia | Mar 17, 2018 |
| Ben Sosoli (inactive) | Combat Wombat | 0-1-0 (1 NC) | Australia | Feb 22, 2020 |
| Krzysztof Soszynski (inactive) | The Polish Experiment | 6-3-0 | Poland | Dec 10, 2011 |
| George Sotiropoulos (inactive) | | 7-4-0 | Australia | Oct 19, 2013 |
| Alex Soto (inactive) | Extremo | 0-2-0 | Mexico | May 15, 2012 |
| Greg Soto (inactive) | | 1-2-0 | United States | Jan 1, 2011 |
| Joe Soto (inactive) | One Bad Mofo | 3-5-0 | United States | Feb 3, 2018 |
| Andre Soukhamthath (inactive) | The Asian Sensation | 2-5-0 | United States | Aug 31, 2019 |
| Manoel Sousa | Manumito | 2-0-0 | Brazil | Aug 8, 2026 |
| Bobby Southworth (inactive) | | 0-1-0 | United States | Apr 9, 2005 |
| Bruno Souza (inactive) | The Tiger | 0-2-0 | Brazil | Mar 26, 2022 |
| Edimilson Souza (inactive) | Kevin | 3-1-0 | Unknown | Nov 7, 2015 |
| Jacare Souza (inactive) | | 9-7-0 | Unknown | May 15, 2021 |
| Jose Souza | Canela | 1-0-0 | Unknown | May 30, 2026 |
| Ketlen Souza | Esquentadinha | 4-3-0 | Brazil | Jun 6, 2026 |
| Livinha Souza (inactive) | The Brazilian Gangsta | 3-3-0 | Brazil | Oct 23, 2021 |
| Chris Spang (inactive) | The Kiss | 0-1-0 | Sweden | Apr 6, 2013 |
| Ryan Spann | Superman | 10-7-0 | United States | Sep 5, 2026 |
| Marina Spasic | Maki Beki | 0-1-0 | Serbia | Aug 1, 2026 |
| Tommy Speer (inactive) | | 0-2-0 | United States | Apr 2, 2008 |
| Felicia Spencer (inactive) | FeeNom | 3-3-0 | Canada | Nov 13, 2021 |
| Sean Spencer (inactive) | Black Magic | 3-5-0 | United States | Sep 10, 2016 |
| Eric Spicely (inactive) | Zebrinha | 2-5-0 | United States | Jun 22, 2019 |
| Daniel Spitz (inactive) | | 1-3-0 | United States | Oct 18, 2019 |
| Serghei Spivac | Polar Bear | 9-7-0 | Moldova | Aug 22, 2026 |
| Daniel Spohn (inactive) | Dragon | 0-1-0 | Unknown | Jul 6, 2014 |
| Pete Spratt (inactive) | The Secret Weapon | 3-4-0 | United States | Jun 12, 2007 |
| Austin Springer (inactive) | | 0-1-0 | United States | Aug 29, 2020 |
| Georges St-Pierre (inactive) | Rush | 20-2-0 | Canada | Nov 4, 2017 |
| Andreas Stahl (inactive) | Real Steel | 0-2-0 | Sweden | Dec 10, 2015 |
| Ron Stallings (inactive) | The Choir Boy | 1-2-0 | United States | Sep 5, 2015 |
| Cody Stamann (inactive) | The Spartan | 7-7-1 | United States | Nov 9, 2024 |
| Cristina Stanciu (inactive) | Barbie | 0-2-0 | Romania | Jul 13, 2016 |
| Brian Stann (inactive) | All American | 6-5-0 | United States | Mar 2, 2013 |
| Josh Stansbury (inactive) | The Sandman | 1-2-0 | United States | Jun 25, 2017 |
| Clifford Starks (inactive) | | 1-2-0 | United States | Apr 20, 2013 |
| Kalib Starnes (inactive) | | 2-3-0 | Canada | Apr 19, 2008 |
| Laureano Staropoli (inactive) | Pepi | 2-4-0 | Argentina | Oct 23, 2021 |
| Damian Stasiak (inactive) | Webster | 2-4-0 | Poland | Jul 22, 2018 |
| Dominique Steele (inactive) | Non-Stop Action-Packed | 1-4-0 | Unknown | Jun 10, 2017 |
| Kody Steele | | 1-1-0 | United States | May 2, 2026 |
| Steve Steinbeiss (inactive) | The Hooligan | 0-2-0 | United States | Aug 1, 2010 |
| Dmitri Stepanov (inactive) | | 0-1-0 | United States | May 30, 1997 |
| Jeremy Stephens | Lil' Heathen | 15-20-0 (1 NC) | United States | May 9, 2026 |
| Aljamain Sterling | Funk Master | 18-5-0 | United States | Apr 25, 2026 |
| Joe Stevenson (inactive) | Daddy | 8-8-0 | United States | Jun 26, 2011 |
| Maia Stevenson (inactive) | | 0-1-0 | United States | Feb 3, 2018 |
| Gable Steveson | | 1-1-0 | United States | Sep 19, 2026 |
| Darren Stewart (inactive) | The Dentist | 5-7-0 (2 NC) | United Kingdom | Aug 28, 2021 |
| Kyle Stewart (inactive) | Gunz Up | 0-2-0 | United States | Jul 27, 2019 |
| Alex Stiebling (inactive) | The Brazilian Killa | 0-1-0 | Unknown | Nov 17, 2000 |
| Navajo Stirling | | 6-0-0 | New Zealand | Aug 1, 2026 |
| Dan Stittgen (inactive) | The Anvil | 0-2-0 | United States | Jul 11, 2012 |
| Denis Stojnic (inactive) | | 0-2-0 | Unknown | Jun 13, 2009 |
| Julija Stoliarenko (inactive) | | 2-7-0 | Lithuania | Aug 9, 2025 |
| Dustin Stoltzfus | | 4-7-0 | United States | Aug 15, 2026 |
| Niklas Stolze (inactive) | Green Mask | 0-3-0 | Germany | Jun 4, 2022 |
| Ken Stone (inactive) | | 2-2-0 | United States | Aug 11, 2012 |
| Rick Story (inactive) | The Horror | 12-7-0 | United States | Aug 20, 2016 |
| Darko Stosic (inactive) | | 1-3-0 | Serbia | Jan 25, 2020 |
| Greg Stott (inactive) | Ranger | 0-1-0 | United States | Oct 17, 1997 |
| Curtis Stout (inactive) | | 0-2-0 | United States | Jun 19, 2004 |
| Sam Stout (inactive) | Hands of Stone | 9-11-0 | United States | Aug 23, 2015 |
| Jesse Strader (inactive) | Sui Generis | 0-2-0 | United States | Feb 19, 2022 |
| Dave Strasser (inactive) | | 1-1-0 | United States | Sep 26, 2003 |
| Gerald Strebendt (inactive) | The Finishing Machine | 0-1-0 | United States | Sep 26, 2003 |
| Sean Strickland | | 18-7-0 | United States | May 9, 2026 |
| Mark Striegl (inactive) | Mugen | 0-2-0 | Japan | Feb 19, 2022 |
| Hans Stringer (inactive) | | 1-2-0 | United States | Jul 18, 2015 |
| Stefan Struve (inactive) | Skyscraper | 13-11-0 | Netherlands | Oct 24, 2020 |
| Josh Stuart (inactive) | | 0-1-0 | United States | Mar 13, 1998 |
| Mike Stumpf (inactive) | | 0-2-0 | United States | Jan 26, 2013 |
| Tatiana Suarez | | 9-1-0 | United States | Apr 11, 2026 |
| Genki Sudo (inactive) | Neo-Samurai | 2-1-0 | Japan | Apr 2, 2004 |
| Sulangrangbo | | 0-1-0 | China | Jan 31, 2026 |
| George Sullivan (inactive) | The Silencer | 3-4-0 | United States | Aug 25, 2018 |
| Amar Suloev (inactive) | | 0-2-0 | Armenia | May 10, 2002 |
| Sumudaerji | The Tibetan Eagle | 7-4-0 (1 NC) | China | Aug 29, 2026 |
| Baisangur Susurkaev | The Real Hunter | 3-0-0 | Russia | May 9, 2026 |
| Louie Sutherland | Vanilla Gorilla | 1-3-0 | United Kingdom | Aug 8, 2026 |
| Joel Sutton (inactive) | | 2-0-0 | Unknown | Sep 8, 1995 |
| Martin Svensson (inactive) | | 0-1-0 | Sweden | Feb 27, 2016 |
| Cub Swanson (inactive) | | 16-10-0 | United States | Apr 11, 2026 |
| Mike Swick (inactive) | Quick | 10-5-0 | United States | Jul 11, 2015 |
| Floyd Sword (inactive) | | 0-1-0 | United States | Jun 23, 2007 |
| Oumar Sy | | 3-3-0 | France | Sep 5, 2026 |
| Klaudia Sygula | | 2-2-0 | Poland | Sep 5, 2026 |
| Bentley Syler (inactive) | Bolivia | 0-1-0 | Bolivia | Mar 21, 2015 |
| Tim Sylvia (inactive) | The Maine-iac | 9-4-0 | United States | Feb 2, 2008 |
| Sebastian Szalay | Seb | 0-1-0 | Australia | Jan 31, 2026 |