| JiobitB2B | B2B | Chicago, United States | John Renaldi | jiobit.com |
| JoltsynsorB2B | B2B | Cambridge, United Kingdom | — | joltsynsor.com |
| JomeB2B | B2B | Brooklyn, United States | — | jome.com |
| Julius TechnologiesB2B | B2B | Old Tappan, United States | — | juliustech.co |
| Jump n PassFintech | Fintech | Culver City, United States | — | jumpnpass.com |
| JustsnapOther | Other | Berlin, Germany | — | justsnap.co |
| JuxtabyteFintech | Fintech | Wollstonecraft, Australia | — | juxtabyte.com |
| KaavioOther | Other | Danville, United States | — | kaavio.ai |
| KadeyaOther | Other | Chicago, United States | Heidi Jannenga | kadeya.com |
| Kairos Sports TechOther | Other | Belfast, United Kingdom | — | kairostech.io |
| Kaizen DesignB2B | B2B | Kearney, United States | — | thekaizendesign.com |
| KandaB2B | B2B | Aarhus, Denmark | — | kanda.dk |
| KapostOther | Other | Boulder, United States | Toby Murdock | kapost.com |
| KardFintech | Fintech | New York City, United States | Ben Mackinnon | getkard.com |
| KartoriumIndustrials | Industrials | Anchorage, United States | — | kartorium.com |
| KatansoFintech | Fintech | Mainz, Germany | — | kumo.earth |
| Kayhan SpaceB2B | B2B | Lafayette, United States | Araz Feyzi | kayhan.space |
| Kazadi EnterprisesIndustrials | Industrials | Batavia, United States | Tristan Kazadi | kazadienterprises.com |
| keen homeB2B | B2B | New York City, United States | Ryan Fant | keenhome.io |
| KeepeConsumer | Consumer | Seattle, United States | Neel Kashmir | keepe.com |
| kelaHealthB2B | B2B | San Francisco, United States | — | kelahealth.com |
| Kencko FoodsIndustrials | Industrials | Brooklyn, United States | Tomas Froes | kencko.com |
| KensaiB2B | B2B | London, United Kingdom | — | kensai.ai |
| Kepler CommunicationsIndustrials | Industrials | Toronto, Canada | Mina Mitry | kepler.space |
| Kestrel LabsOther | Other | Denver, United States | — | kestrellabs.com |
| Kestrl: Muslim Money AppFintech | Fintech | Waltham Abbey, United Kingdom | — | kestrl.io |
| KeysConsumer | Consumer | Missoula, United States | — | charmed.app |
| KeystoneBioHealthcare | Healthcare | Columbus, United States | — | keystonebio.co |
| Khaki AIOther | Other | Columbus, United States | — | khaki.email |
| KidasB2B | B2B | Philadelphia, United States | Daniel Donahoo | getkidas.com |
| KiddoWearOther | Other | San Francisco, United States | — | kiddowear.com |
| KilsarOther | Other | Virginia Beach, United States | — | kilsar.com |
| KimbaHealthcare | Healthcare | Tel Aviv, Israel | — | kimba.ai |
| KindredPMB2B | B2B | New York City, United States | — | kindredpm.ai |
| KineticOther | Other | New York City, United States | Haig Nalbandian | kineticcomp.com |
| KinometrixB2B | B2B | Fort Belvoir, United States | — | kinometrix.com |
| KinsideFintech | Fintech | Pasadena, United States | Erin Luck | kinside.com |
| KitchenMateOther | Other | Toronto, Canada | Amir Farha | kitchenmate.com |
| Kitchn.ioB2B | B2B | Berlin, Germany | — | kitchn.io |
| KITROOther | Other | Renens, Switzerland | Eleanor Curry | kitro.ch |
| KlaimIndustrials | Industrials | Abu Dhabi, United Arab Emirates | Ali Jaffer | klaim.ai |
| Klira AIOther | Other | San Francisco, United States | — | getklira.com |
| KnitConsumer | Consumer | Suffolk, United States | Eshaan Mitra | goknit.com |
| KoalaFintech | Fintech | Paris, France | — | hikoala.co |
| Koda HealthOther | Other | Houston, United States | Sonsoles Gonzalez | kodahealthcare.com |
| Korall EngineeringOther | Other | Bergen, Norway | — | korall.io |
| KredeteFintech | Fintech | New York City, United States | — | kredete.io |
| KriptosB2B | B2B | Tiburon, United States | — | kriptos.io |
| KumudaHealthcare | Healthcare | Boston, United States | — | kumuda.org |
| Kura TechnologiesFintech | Fintech | Boston, United States | — | kuratek.com |