I'm pretty skinny, weighing 145 at 5'11". I got the medium and it fits GREAT. It's decently snug with a little room, and the sleeves are a perfect length, just a little long. The only thing that's a little tough is that it's not incredibly flexible, so don't expect to do anything super active in it. If I put my arms straight forward the back is pretty tight, and if I put them straight up the whole coat comes with it. It's perfectly fine for normal wear, but any hard physical activity might do some damage. It's not terribly thick, but is great for cooler spring/summer nights. I was skeptical to buy something like this online, but I have no regrets.