The XOOPS Theme Directory is the themes/ folder from the main XOOPS directory. Any folder within that directory is considered a theme. With the default installation, there are 3 folders available that represent the 3 themes: default/, phpkaox/ and x2t/.

It is important to remember that when you install your theme inside the Theme Directory, the folder name of your theme becomes the name of the theme from within the XOOPS Admin Control Panel.