I ordered this shirt in a medium for my 8 year old, who is tall for his age.   He normally wears a size 10 or medium.  Although I ordered a (M), the shirt is too small.  The color and quality are great, so I'm exchanging it for a larger size.   The collar was one of my son's concerns.  He didn't want it to be too high and it's not. It's just high enough to protect the back of his neck without feeling like he's wearing a turtleneck.