I am in the XL because they didn’t have a large and the medium looked sus. I would say a large would fit me best but imma be real honest — I do not mind this slouch. This dress is a chambray dream. It’s that soft tencel fabric and it’s slinky, soft, super cute. Comes in lots of colors too! I would say size up one if you have boobs for sure. Otherwise, you may be okay.