I normally wear a Large or a size 10/12. After reading reviews I ordered a large and it fits perfectly. I love this dress. Not sure if I will keep it in this color or exchange for a different color as I purchased it for an upcoming Disney trip and was hoping it was a bit lighter blue to match a more classic Minnie, but it spins great - my 3 year old loved having me spin it while she was in dress up clothes. Very comfortable and flattering.