XOOPS can support multi-byte character sets 'out of the box'. The language of the user interface can be changed by installing additional language packs. Currently available packs include Dutch, French, Italian, Russian, Spanish, Swedish, Arabic, Japanese and Chinese (both simplified and traditional).

The language files are easily located and modified due to the modular nature of XOOPS. Creating additional language packs for modules is as simple as copying a language folder and translating the text strings.