I am 5'7" 130 lbs and bought a the navy in size medium, my usual size. It fits quite well. I pair it with a tan/brown belt at the waist otherwise it looks like a moomoo, and that's just not cute. Also, the top part is a little see through, like the other reviews say, but a nude strapless bra does the trick, unless you're into exposing your assets.
Great purchase for the price. Just what I was looking for! Comfy summer dress for any occasion. Being a momma- I'm always looking for things just like this- you can dress it up or down- and it has pockets!! Can't get much better.
Only complaint I had was took a while to ship.... but it was definitely worth the wait. I will be ordering more in other colors.