| Zaytuna College | college, seminary, university | — | 2008 |
| Zello | business | New York, Austin | — |
| Zendesk | software company, technology company, business, public company | San Francisco | 2007 |
| ZeniMax Online Studios | video game developer | Hunt Valley | 2007 |
| Zenith Electronics | organization, business, enterprise | — | 1918 |
| Zero Tolerance | film production company, pornographic film studio | Los Angeles | 2002 |
| Zillow | website, business, online real estate database, enterprise, public company | Seattle | 2006 |
| Zilog | business, enterprise | San Jose | 1974 |
| Zimmer Biomet Holdings | business, enterprise, public company | Warsaw | 1927 |
| Zippo | privately held company | Bradford | 1932 |
| Zoox | business | Foster City | 2014 |
| Zscaler | business, public company | San Jose | 2008 |
| Zynga | video game developer, public company | San Francisco | 2007 |