Although i'm somewhat of an athletic build, I bought a Medium and it came VERY quickly.  The rayon is just amazing fabric.  It came in packaging folded, so it needs to hang a couple days to get the rest of the wrinkles out.  I'm 140 pounds, and 5'10 and really think that this dress will look flattering this summer with some nice sandals or 2 inch white heals. I can't wait to wear it to somewhere exotic.  It feels VERY breathable and is EXCELLENT quality for the price.  Size is very true.