Living in Overijse

Go and look yourself on the map.
http://www.delijn.be/images/netplan_vervoergebied_Brussel_07012013_tcm7-...

You can look up all the bus timetables on the de Lijn website. Overijse is a big gemeente, just find your nearest stop on the map and the stop where you want to go to, see which buses run between. There is a Leuven map on the de Lijn website too showing where the buses go between Ovrejse and Leuven.