| Seabreeze Software | Auckland |
| Seamless Webtools | Auckland |
| SearchMasters 2015 Ltd | Manawatu-Wanganui |
| Searle Electronics | Northland |
| Second Mile Internet Solutions | Bay of Plenty |
| SecOps | Auckland |
| See Tomorrow First | |
| Seekom | Wellington |
| Seequent | Canterbury |
| Sektor Ltd | Auckland |
| Sentient Software Ltd | Auckland |
| SEOPro NZ Ltd | Auckland |
| Serko Ltd | Auckland |
| Serrata Systems & Software Ltd | Auckland |
| Service Plus Group Ltd | Auckland |
| SeventyTwo | Auckland |
| ShadowTech | |
| SharedPod | Wellington |
| Sharedspace | Auckland |
| Sharesies Ltd | |
| Shinywhitebox Ltd | Wellington |
| Signify Ltd | Wellington |
| Silicon | Wellington |
| Silicon Dream Ltd | Auckland |
| Silicon Logic | Auckland |
| Silverstripe | Wellington |
| SilverStripe Ltd | Wellington |
| Simplehosting | Otago |
| Simplicity Australasia Ltd | Auckland |
| SimplyWebsites | Canterbury |
| Simpson Design | Wellington |
| Sisters in Tech | |
| Site Design & Hosting Ltd | Waikato |
| Site Productions | Nelson |
| Sitehost | Auckland |
| Sky SEO | |
| Slingshot | Auckland |
| Smart Computers Systems Ltd | Canterbury |
| Smart Newtown | Auckland |
| SmartMail Pro | Auckland |
| SmartPayroll | Wellington |
| Smartrak Ltd | Waikato |
| Smegoweb | |
| Smetric Insights Ltd | Auckland |
| Smokeylemon | Taranaki |
| Smoother Solutions Ltd | Bay of Plenty |
| SMTP2GO | Canterbury |
| SMX | Auckland |
| SnapComms | Auckland |
| Snapper Network Distributors Ltd | Auckland |