Bought 2 one in 4/5 and 12/14. I have a 4 yo and 8yo regular size for my 4yo is 4t/5t and the shirt was a little long but nice fitting my lo is a little shorter then most....the 12/14 I ordered for my 8yo 9 in 2 months fit perfectly he usually wears 12/14 just reached this size so it's room to grow.