Women should note: Just because there's a female model does not make this a women's shirt. It's a unisex (men's) shirt. Therefore, order the size you would normally order in any old standard men's tee. (Though I found it to be just a little baggier than standard). I'm 5'10", 145 lb, 36C and ordered the Small. It was really loose. An XS would have been a much better choice and it would still be a comfortably loose. Also note that the sleeves are baggy, not form-fitting. The fabric was wonderful though - cotton/polyester/rayon mix - very soft and comfy!