| Institut društvenih znanosti Ivo Pilar | |
| Institut Ruđer Bošković | City of Zagreb |
| Institut za društvena istraživanja u Zagrebu | |
| Institut za elektroprivredu d.d. | |
| Institut za fiziku | |
| Institut za javne financije | |
| Institut za medicinska istraživanja i medicinu rada | |
| InsulaBit j.d.o.o. | City of Zagreb |
| IntegraCAD | Primorje-Gorski Kotar |
| Intel d.o.o. | |
| Intellegens j.d.o.o. | |
| INTELLEXI d.o.o. | |
| Inter-BIZ | Varaždin |
| Inter-Comp d.o.o. | |
| Interactive1 Zagreb d.o.o. | City of Zagreb |
| Interdata d.o.o. | City of Zagreb |
| Internetske stranice Nacionalnog CERT-a | City of Zagreb |
| Internetsko novinarstvo d.o.o. | |
| InterSoft d.o.o. | |
| INTERWEB d.o.o. | Primorje-Gorski Kotar |
| Intesis d.o.o. | City of Zagreb |
| Intouch Interface | |
| Inventa IR2 d.o.o. | City of Zagreb |
| Inventum | City of Zagreb |
| Ipsum d.o.o. | Dubrovnik-Neretva |
| iQ Agencija | |
| Iqmedia | Požega-Slavonia |
| Irata d.o.o. | City of Zagreb |
| Iskon Internet d.d. | City of Zagreb |
| Istarsko veleučilište | |
| Istra Tech d.o.o. | Istria |
| IT Consulting Services d.o.o. | |
| IT Jedan d.o.o. | City of Zagreb |
| IT.inteligentne tehnologije d.o.o. | City of Zagreb |
| ITB internet usluge j.d.o.o. | Krapina-Zagorje |
| ITDesign | |
| Item d.o.o. | Split-Dalmatia |
| IV Ci d.o.o. | City of Zagreb |
| J-Sistem d.o.o. | Međimurje |
| Jadran Informatika d.o.o. | Primorje-Gorski Kotar |
| Jadrija d.o.o. | City of Zagreb |
| Janus PIM d.o.o. | |
| Jasob JavaScript Obfuscator | City of Zagreb |
| JAVV Digital | |
| JS Mastery Pro | |
| Judge0 d.o.o. | |
| Jupiter Software | Osijek-Baranja |
| K. G. Media d.o.o. | Istria |
| Kalelarga.net | City of Zagreb |
| Kalo.dev j.d.o.o. | City of Zagreb |