| Sharedspace | Auckland |
| Sharesies Ltd | |
| Shinywhitebox Ltd | Wellington |
| Signify Ltd | Wellington |
| Silicon | Wellington |
| Silicon Dream Ltd | Auckland |
| Silicon Logic | Auckland |
| Siliconcoach | |
| Silverstripe | Wellington |
| SilverStripe Ltd | Wellington |
| Simple Brackets Ltd | |
| Simplehosting | Otago |
| Simplicity Australasia Ltd | Auckland |
| Simply Free | |
| Simply Training Co. Ltd | |
| SimplySEO NZ | |
| SimplyWebsites | Canterbury |
| Simpson Design | Wellington |
| Sisters in Tech | |
| Site Design & Hosting Ltd | Waikato |
| Site Productions | Nelson |
| Sitehost | Auckland |
| SiteTools | |
| Sky Media | |
| Sky SEO | |
| Skyrocket | |
| Slightly Different | |
| Slingshot | Auckland |
| Smart Computers Systems Ltd | Canterbury |
| Smart Newtown | Auckland |
| SmartMail Pro | Auckland |
| SmartPayroll | Wellington |
| Smartphone Repairs | |
| Smartrak Ltd | Waikato |
| SmartTech.nz | |
| SMEDiGi | |
| Smegoweb | |
| Smetric Insights Ltd | Auckland |
| Smokeylemon | Taranaki |
| Smoother Solutions Ltd | Bay of Plenty |
| SMTP2GO | Canterbury |
| Smuge | |
| SMX New Zealand Ltd | Auckland |
| SnapComms | Auckland |
| SnapInspect | |
| Snapper Network Distributors Ltd | Auckland |
| Snipesoft Ltd | Auckland |
| Snowball Effect | Auckland |
| Soda, Inc. | Waikato |
| SoEasy | Bay of Plenty |