I bought this first in a 2XL but the collar wasn't sitting right but I kept it anyway cuz it wasn't that bad. Then I ordered another one in an XL and it fits perfectly!  O yea, the 2XL one I had to cut the extra black thingy in the inside of the opening becuz it wasn't laying rite either. This kind of shirt really hugs u so don't get it if u have a big gut. My measurements are: 38-40in chest, 15 1/2in biceps and a 30in waist. Oh and I'm 5'9, 170lbs