Richie House Big Girls' Sweet Sundress with Lace Rh0980 100% Cotton Lining: 100% Polyester Little ladies will be the belle of the ball donning this darling dress. For a day spent outdoors or an afternoon with pals, this dress is great for little sweeties. A size 2/3 is for the average 2-3 year old girl, a size 5/6 is for the average 5-6 year old girl, a size 9/10 is for the average 9-10 year old,etc