Adorable shirt. I got a medium but probably could have gotten a small as well. The shirt is sheer, but not obviously so. I could probably get away with a bra or bandeau if I'm wearing it to a bar but will definitely need something under it for work or something more formal. My only complaint is with the look of the button around the neck. It's bright white and plastic and stands out. I will probably try to replace it with a navy fabric covered button.