Can anyone clarify what the class sizes are? Any small, discussion based classes...?

Colleges and Universities A-Z McGill University
1

I heard the classes have hundreds of students. Is that the case for all classes?

2

First year classes will be large as at any public university. there are discussion sections.

3

Classes that are required for general education are generally large but classes that are for the major are normal sized. You can check how large a class is when you see how many people are allowed to sign up for a single class.