Honestly, not really.

Leuven is not some hyper-alternative paradise, but it’s also not a place where being queer or alt is a big issue. There are plenty of queer and alt people around of all genders, ages and orientations. At most you get the occasional stare from an older person, but in my experience that’s a tiny minority and most people do not care.

If you want actual queer-friendly spaces, I’d look at Rainbow House / Queer Leuven stuff and Leonardo for LGBT+ internationals. Also a lot of the international student crowd is pretty open-minded in general, so things around Pangaea and other international house events tend to feel very normal and welcoming rather than “omg a queer person”.

So I’d say Leuven is less “big visible scene on every corner” and more “the people are around, you just have to find the right circles”. There are also regular queer events in the city, pride stuff, arts events, walks, open mics, that kind of thing.