My 4.5 year old daughter wears size 11 sneakers and clothes 5-5T. I bought black size 4-6. They're too big for her, but she can eventually grow in them, and the material is cheap and her feet can't breathe through the material. Those are smelly socks. She'll probably wear them with shoes because they're so thin. I also bought white ones, I hope they are cotton as the description says.