In what way do you mean? Language or Right To Left (RTL) support?
Glide supports Arabic as a language for the built in verbiage of the glide interface. However, it will not translate data from you tables into Arabic. You would have to build that functionality yourself, but if you want built in text to translate, that will happen automatically based on the regional language that a user has selected on their device and browser.
If you are talking about RTL support, then Glide does not currently support that. Many have used a lot of CSS give apps an RTL feel. Pages do not allow for CSS, but Apps do.
There are several posts regarding the use of CSS to force RTL. This is the latest.
This is a feature request that you can vote on to request RTL support.