I'm 5'11", 155 lbs and the medium fits me perfectly. I haven't washed it yet, but I'm hoping the 2% spandex means it won't shrink much. However, the shirt I received is slightly different from the shirt pictured. I ordered the Ocean color, and the buttons are the same shade as the shirt (dark teal) instead of the dark brown pictured. Also, the pocket logo is not a tag with the word "Billabong", but the stitched logo used on most other shirts. I think the shirt still looks good, just a little less professional than I had expected (the main reason I chose it was because I wanted to remove the tag on the pocket).