Verified answer

My friends and I wear jeans and t-shirts, even when we're teaching labs. Our professors wear the same if they aren't teaching. Of course, we're all science students, and no one expects us to look all that professional - it might depend on the program.

Graduate School Dress Code

The only time I would dress more professional was if I was coordinating events for my student organization, going to an awards ceremony or other large scale function at school where other professionals might have been at. In class and at work (grad student assistant in a library) - very casual: t-shirt, jeans, sneaks.

I suppose I have seen MBA students dress more professional. In the same breath, law students never dress professional unless they're doing things like I mentioned above. Hence, it may depend on which grad program you're in.

I just finished grad school in the UK. I wasn't remotely dressy and neither was anyone else.

Except for students at Oxford and Cambridge being required to wear academic robes while taking exams I haven't heard of any grad school anywhere requiring formal attire outside of ceremonial (ie graduation) events.