I am 5'11" and 173 lbs and the size medium if form fitting, which I wanted. If you want to wear it a bit looser, order one size up. This is a light-weight t-shirt, which is what I wanted for my hot climate. I'm buying several more in different colors right now. Made in El Salvador of good quality cotton, with excellent workmanship. Much better than the Made in China shirts I bought last year.