I am 5' 6", 152 lbs and wear a size 10. I bought a large and they fit perfect, very comfortable. I'm glad I bought these, and that I bought a 2nd pair (a different color). I like that it has a cell phone pocket on both legs, plus it has a little pocket (to hold your ID, a key, etc) in the front top-left side. I've had other leggings that have a band that is too tight at the very top going all the way around, enough so to make the leggings uncomfortable, but these are just perfect.