I normally wear a medium in dress shirts. I'm 6 foot and 167lbs and a 33 inch waist. I had to get a Large in this jacket but it fits perfect. Best looking jacket I have ever worn. Very happy with it. I normally wear a 40R jacket but when it comes to S M L jackets, Its usually a toss up between M and L. Was a little expensive but it was a birthday gift from my wife.