5'9. He normally wears a 1x. I ordered him a 3x. The fit was nice, but a little short in the back. A 4x would have been perfect... to account for the back, and shrinkage from the washer. I also ordered a couple for myself. Female. 5'3. I normally wear M/L. I ordered myself a xLarge. Perfect fit, and it was not short in the back. Buy a size, or 2 up!