I usually order smalls but spur of the moment I decided to get a medium and it fits PERFECT! I love this pj set. I’ve already put it in the wash so I can wear it tonight. It is soft, comfy, and ADORABLE!!!!! I would recommend that you size up one size and it should fit perfect. I could have done a small, but the medium is just right for bedtime. You can’t go wrong with this and so worth the price. I’m 5’5” 125lbs.