"My son loves Mickey Mouse so much and I knew this was what he was going to be for Halloween. I was never thrilled with this costume because it doesn't look like typical Mickey but I couldn't find one I liked better so I bought this. My son is 26 months old and in size 4T clothing. I bought the 3T/4T size which fits perfectly. There is enough room underneath for a small layer of clothing as we live in Ohio and it is always cold. However, as every other review the headpiece is TINY. My son is 2 and it doesn't fit him, I can't imagine actually trying to put it on a 3 or 4 year old. Everyone else is correct saying the size is for an infant. I have my own Mickey ears so I am not as upset as I should be. If I buy something I want it to fit right."