Beautiful dress! I am 5'5" and usually wear a size 6, usually a medium and the large fit me like a glove. I am also 34DD and it fit perfectly, but due to the neckline, I would say any less than a C cup might have trouble getting the top to stay in place. There is elastic that is supposed to hold in place, but it moved throughout the night. Still, this dress is very beautiful and looks better in person. Very flattering!! Size up though. 5 stars because I loved it!