| SeatedConsumer | Consumer | New York City, United States | Bo Peabody | seated.com |
| Seated With LoveOther | Other | Ann Arbor, United States | — | seatedwithlove.com |
| Secret SkinIndustrials | Industrials | Dubai, United Arab Emirates | — | thesecretskin.com |
| Sedso.aiB2B | B2B | Singapore, Singapore | — | sedso.ai |
| Seed&SparkFintech | Fintech | Los Angeles, United States | Emily Best | seedandspark.com |
| SeedsightOther | Other | — | — | seedsight.io |
| SeekWellB2B | B2B | New York City, United States | James Donahue | seekwell.io |
| SeelFintech | Fintech | Sunnyvale, United States | Chester Ng | seel.com |
| SeeO2 EnergyIndustrials | Industrials | Calgary, Canada | — | seeo2energy.com |
| Seer AerospaceIndustrials | Industrials | New York City, United States | — | seeraerospace.com |
| sees.aiOther | Other | London, United Kingdom | — | sees.ai |
| SegmentStreamOther | Other | London, United Kingdom | Dmitry Melnikov | segmentstream.com |
| SeldonOther | Other | London, United Kingdom | Clive Cox | seldon.io |
| SelfFintech | Fintech | Austin, United States | James Garvey | self.inc |
| SendbirdConsumer | Consumer | San Mateo, United States | John S. Kim | sendbird.com |
| SendGridConsumer | Consumer | Denver, United States | Isaac Saldana | sendgrid.com |
| SenexxOther | Other | Cambridge, United States | — | senexx.com |
| Sensate RoboticsOther | Other | Los Angeles, United States | — | sensate-robotics.com |
| SensefinityOther | Other | Lisbon, Portugal | Pedro Félix | sensefinity.com |
| SenseiOther | Other | Lisbon, Portugal | Ingrid Alongi | sensei.tech |
| SenseITB2B | B2B | Tel Aviv, Israel | — | senseit360.com |
| Sensible ObjectConsumer | Consumer | London, United Kingdom | Alex Fleetwood | sensibleobject.com |
| Senso.aiB2B | B2B | Toronto, Canada | Robb Nabb | senso.ai |
| SensytecIndustrials | Industrials | Houston, United States | — | sensytec.com |
| Sentiment SearchOther | Other | London, United Kingdom | — | sentimentsearch.com |
| SequelB2B | B2B | San Jose, United States | — | sequel.io |
| SequrConsumer | Consumer | Atlanta, United States | James Segil | sequr.io |
| Serve FirstOther | Other | Epping, United Kingdom | — | servefirst.co.uk |
| ServeScapeIndustrials | Industrials | Chamblee, United States | — | servescape.net |
| SheevaFintech | Fintech | Alexandria, United States | Nir Shmueli | sheeva.ai |
| Shelby.tvOther | Other | New York City, United States | Anjali Mullany | shelby.tv |
| Shelf.NetworkFintech | Fintech | Berlin, Germany | — | shelf.network |
| ShieldpayFintech | Fintech | London, United Kingdom | Tom Clementson | shieldpay.com |
| ShiperiseFintech | Fintech | Brussels, Belgium | — | shiperise.com |
| ShippableOther | Other | Bellevue, United States | Avi Cavale | shippable.com |
| Shipshape Urban FarmsIndustrials | Industrials | Mobile, United States | — | shipshapeurbanfarms.com |
| SholderHealthcare | Healthcare | Boulder, United States | — | sholder.com |
| ShookB2B | B2B | Tzur Hadassah, Israel | — | shoook.io |
| Shop LatinxOther | Other | Los Angeles, United States | — | shoplatinx.com |
| ShoppermotionOther | Other | San Francisco, United States | Sergi Palau | shoppermotion.com |
| ShopventoryFintech | Fintech | San Diego, United States | Brandon Billinger | shopventory.com |
| ShurpaIndustrials | Industrials | Chicago, United States | — | shurpa.com |
| SideTourOther | Other | New York City, United States | Vipin Porwal | sidetour.com |
| Sidewalk InsuranceOther | Other | New York City, United States | — | sidewalk.biz |
| SIEMonsterB2B | B2B | New York City, United States | — | siemonster.com |
| Sigma RatingsOther | Other | New York City, United States | Stuart Jones | sigmaratings.com |
| SignalOther | Other | Novi, United States | — | signal.co |
| SignalOpsB2B | B2B | Jamaica, United States | — | cadena.dev |
| Silene BiotechHealthcare | Healthcare | Seattle, United States | — | silenebiotech.com |
| SilversheetOther | Other | Culver City, United States | Daniel Kivatinos | silversheet.com |