I've bought this sweater for my 6yo twice now, and have been disappointed both times. Last time, I bought a 7 because he's tall. He got 2 wears out of it and then we had to donate it; figured it just ran a bit snug and I needed to order a size up. This time I bought 2 8s - 1 grey, 1 orange. The t-shirts I ordered for him fit well, and are VISIBLY different in size than this. The sweaters look so snug he'll be lucky to get 4 wears before donation this time, but only because I hedged my bets and bought 2.