I went with a medium - I'm 5' 2" and (ah em) 145 pounds. I was thinking I'd need the large, but the medium was perfect. I wish this rash tee had a built in bra or bra shelf or something ---- but I get that these are to be worn over a bikini top or perhaps for a younger gal who doesn't need the shelf :) At any rate, it was great for a weekend at the indoor water park where I'm just not comfortable walking around nearly naked...I need the blazing sun for that.