Based on the reviews, had to take a guess at sizing. Went with Medium for 5'10", 183 lb, size 33 pant waistline. It does seem to be a slimmer fit at the bottom of the jacket, but not tight. Fits well, looks good. Four out of Five stars only because I believe the reviewers that the zipper doesn't / won't last. I'll try to not use the zipper much, and perhaps - if I like the jacket enough, have the zipper replaced. It seems to be a good looking enough jacket for now.See full review