| Title | CMS Category |
|---|---|
| NodeBB | Forum Software |
| nopCommerce | Ecommerce |
| Notion | Groupware Wiki Software |
| Nuclino | Groupware Wiki Software |
| October | Traditional CMS |
| Odoo | Enterprise Solutions |
| Omeka | E-Learning Gallery Software |
| OnePageCRM | CRM Solutions |
| OneWindow | Groupware |
| OnSpace | App Builders |
| Onveos | Ecommerce |
| Open edX | E-Learning |
| Open eLMS | E-Learning |
| Open eShop | Ecommerce |
| Open Exhibits | Specialized CMS |
| Open Web Analytics | CRM Solutions |
| Open-Realty | Specialized CMS |
| OpenCart | Ecommerce |
| OpenCMS | Traditional CMS |
| openCRX | CRM Solutions |