"I ordered the 4-6x for my 4 year old son and he is just fitting into it. The costume runs extremely small. This would never fit a normal 5 or 6 year old kid. If my son grows by Halloween, I'm going to have tweak the costume somehow. It's a shame because it's the only "cute" skeleton costume I've come across. With my son being only 4, I didn't want anything to scary or ghoulish!"