Players ATPWTA
| Name | Country |
|---|---|
| Henrik Sillanpaa | FIN |
| Rogelio Siller | MEX |
| Caio Silva | BRA |
| Frederico Ferreira Silva | POR |
| Julio Silva | BRA |
| Cameron Silverman | USA |
| Florian Simbozel | FRA |
| Juraj Simcak | SVK |
| Gilles Simon | FRA |
| Tobias Simon | GER |
| Fred Simonsson | SWE |
| David Simunek | CZE |
| Dong-Hak Sin | KOR |
| San Hui Sin | KOR |
| Dalwinder Singh | IND |
| Karunuday Singh | IND |
| Sanam Singh | IND |
| Digvijay Singh Mehta | IND |
| Nitin Kumar Sinha | IND |
| Riccardo Sinicropi | ITA |
| Henrik Sinkko | FIN |
| Jannik Sinner | ITA |
| Peerakiat Siriluethaiwattana | THA |
| Stjepan Sisko | CRO |
| Artem Sitak | NZL |
| Rudolf Siwy | CZE |
| Adam Skalsky | GBR |
| Timofey Skatov | KAZ |
| Harry Skinner | GBR |
| Daniel Skripnik | ISR |
| Franko Skugor | CRO |
| Alexander Slabinsky | GBR |
| Ryoma Sloane | NZL |
| Ronald Slobodchikov | RUS |
| Filipp Smalyanyy | RUS |
| Daniel Smethurst | GBR |
| Igor Smilansky | ISR |
| Artem Smirnov | UKR |
| Austin Smith | USA |
| Colton Smith | USA |
| Connor Smith | USA |
| John-Patrick Smith | AUS |
| Logan Smith | USA |
| Raleigh Smith | USA |
| Maciej Smola | POL |
| Tim Smyczek | USA |
| Igor Sobolta | UKR |
| Jack Sock | USA |
| Carl Soderlund | SWE |
| Go Soeda | JPN |