I order from retailer regularly and am pretty consistently a 0 petite or xxs petite. i ordered this in a 0 petite and it was like 5 inches too small in the rib cage and chest area. even if i would have got it zipped up, the halter cut is cut narrow so you can't wear a bra for sure...strapless would be necessary. also, the actual neck part was tight. for reference, i am 5'3", 108 pounds and a 32c bust. it seems you need to be flat chested to pull this one off and maybe missing a few ribs.