Run very large.  I have ordered these in 3 colors from 2 different sellers.  The first time they were way too big and I had ordered what I thought was 1 size up form the size I got her last summer (same shoe last summer).  Ok, too big not so bad she 4, I ordered them in March so she has time to grow.  I ordered another pair in blue from a different seller went down a size and they were the same size I already had.  Overall I love these shoes.  I would not have ordered her a total of 4 pairs of the same shoe in 2 years if we didn't like them.  They are great for wide feet and don't rub blisters on her.