My son couldn't decide on a costume for Halloween. In the end he chose the tiger, but I discouraged his first choice, the lion, because of this suit. I guess the size. The biggest says it's 3T-4T and my son just turned 5. It still fits most of my 4T garments so I took a chance and it fits perfectly. It's not small at all and has plenty of room to move around, so I'd say it's a lot more on the 4T side than the 3T. He likes the mittens and I like that they are attached and don't get lost. The only downside is that when there is cotton candy at the Halloween party, the mane will become sticky. In fact, we couldn't be happier about it, and he's totally come to terms with the fact that he's not a tiger because the lion costume is so wonderful. Pro tip: The hood is fully detachable for easy donning. We didn't find out until the third time that the latches were completely gone and it was a bit difficult to get the main latch on in front of us.