I am 5'5" , 138 pounds and ordered the small.  I normally wear a size 4 or 6 and it fit perfectly, hitting about 4 inches above the knee.  I wore it to a wedding and got lots of compliments.  It is well made of a smooth, Stretchy polyester and spandex blend.  It is very comfortable and hugs your curves nicely.  Worn with nude heels, it is very sexy and classy at the same time.