Which has smaller class sizes, USC or Brown?

The biggest practical tradeoff is that Brown is built around a smaller undergraduate population, while USC is a much larger university with more students and more large introductory courses. If small classes are your priority, Brown is more likely to give you that feel across your overall undergraduate experience. USC absolutely has small seminars and discussion-based classes too, but Brown tends to be the place where knowing professors and classmates feels more built into the structure of the school.

Brown’s undergraduate college is relatively compact, and that usually shows up in class size, especially once you move beyond intro courses. Its open curriculum also means many students end up in smaller, interest-driven classes rather than as many tightly sequenced lecture halls. The campus culture is also more centered on undergraduates, which can make faculty access feel easier and more natural.

USC has plenty of ways to make a big university feel smaller, especially through honors programs, specialized majors, and upper-level coursework. But as a large private research university, it will typically have more big classes in popular departments and a more sprawling overall feel. You can still build close professor relationships there, but it often takes more intentional effort.

So on the specific question of smaller class sizes for undergrads, Brown has the edge. If your top priority is not feeling like one more student in a large system, Brown is the more consistent bet.