I bought a size 4-6 for my 4 year old son last year for Halloween. It fit great and he loved it. He not only wore it trick-or-treating, but throughout the year for dress up. It's roomy enough that he's planning to wear it again this year, along with all the fun accessories (which unfortunately are too big for a 5 year old). It's held up great and still looks new. I would definately recommend this suit to others.