Runs just a touch big, but mainly true to size. This is a great value for all four pieces.  Our vest came heavily creased, which was helped by using a handheld steamer. It wasn't perfect, even with the steaming, but at this price for a four piece set I don't feel like I can complain. (We ordered two vests and one was in worse shape than the other one. The size that fit him was the one with the worst creases. I think the other vest would have steamed out the creases fairly easily.) Customer service responds promptly and efficiently to all communication.