I ordered this for my grandson and got a large by mistake - he is only 6! However the medium I ordered for my older grandson (8) was too small so I was glad that I got the 'wrong' size by mistake. I wish they would put actual sizes on the order site - there weren't any when I ordered - just small, medium or large! No idea what any of them meant. My grandsons are slightly small for their ages too. Nevertheless, the shirts are great quality and my grandsons love the pictures.