I am 5’4” 198 and ordered an XL for reference. It was perfectly roomy. So comfortable. I only wear a bralette under mine as it’s getting pretty warm here already. I could’ve gone up in size (and still might) to get just a little more room, but the XL didn’t ride up (even when I tightened the straps) and felt like a great fit to me. I am so in love with this romper. It is the perfect thickness and the pockets are perfect.