Yes, children are allowed to wear costumes to Walt Disney World! Costumes must be family friendly and adults are not allowed to pretend to be an actual Disney character (no pictures or autographs). You can find the costume guidelines for children and adults here. Tip: Don't wear princess costume shoes to the park. Have your child wear comfortable walking shoes. We have tons of great options here. If she wants to change into princess shoes for a photo, simply pull them out of your park bag!