I bought this Carhartt shirt jacket for my husband.  I paid attention to other reviews, which said the shirt ran large and one person said the size large was HUGE.  So I bought my husband a medium, and it fits perfectly!  He is 5'11" and slim, and sometimes can wear a large, but this Carhartt shirt jacket is long, and roomy enough to fit over a flannel shirt.  We live in cold weather, and he loves this shirt to walk outside or in and out of the car when the temp is in the 30s.  He liked it so much he ordered a second one for himself in another color.  These shirts are well-made and warm.