This jacket runs at least an entire size large, I'm 5'9" and 160 lbs and the small is still roomy once you take the liner out. The BIG flaw with the design of the jacket is the zip in liner. If the liner is zipped in, it gets in the way of the gaiter and it cannot be properly used. Either Quiksilver never actually tested the jacket in real world situations, or they just got lazy with the design. Most likely will return this jacket, which is sad because I really liked the rest of the features.