Very cute dress however it's stretchy material and I ended up taking mine in a lot because it was way too big.  I chose an XXL based on their size chart listed in the description (XXL: Bust 40.2". Waist 32.3"-44.1"), even though my bust is bigger than 40" and my waist is 35".  I probably would have gone for a Large.  My kid got the 7T even though she wears 8-10.  Fits her fine with room to grow.  Would easily fit her for another couple years.