I am 6'0" about 185# and somewhere between a slender to medium build. My shirt size is 16-1/2" Neck by 32/33 sleeve. I originally ordered the Large size, a size that usually fits me, and the jacket fit was just too big. Too wide in the shoulders, too big in the chest/waist, and too long in the sleeves. Judging from that fit, the size guide chart indicated that from the measurement differences between the Large and Medium, that the Medium should probably fit me. I ordered the Medium and it fits aSee full review