I listened to other women and ordered a large, which I usually order for tops. I'm 5'5, 158 lbs, 38A/B cup size. It was way too big. The arm hole openings were gaping and I could button it up with extra room. I wanted to have it open over my clothes. I could probably close up a medium easily. I'm hoping they'll let me exchange it - couldn't find an option to though, only a refund.