My son is 19 mths and I got this shirt in 2T and it fits him perfectly. Its the right size where you can still put on another tshirt underneath. Its made out of good material also.
The blue on this shirt was a lot brighter than what is pictured. It does fit my son, but the pants that we got to go with this, does not match. I am ok with it because we use it for a sleeping shirt.
This shirt is very nice quality - not cheaply made! I think this is a bit on the larger size - can't see this fitting my son until next fall (he will be 3 in March), but that's not a bad thing!