I ordered a Medium and it is super tight. (I normally wear a Medium). I ordered several different style shirts and the sizing is all over the place, mainly too small.
These t shirts live up to their billing. Best part is they are priced well. Have seen some other companies try to sell tshirts for $60. Will be back for more...and my wife wants a few now as well.
I'm about to order two more of these, after purchasing two a few months ago. These tees are seriously the softest, most comfortable, form-fitting-yet-stretchy tees ever. I live in these bad boys, and the deep V-neck is a super flattering cut too (I'm a curvier girl and I get more compliments on my outfit wearing these than I do when I wear a dress).