The size that comes after 24 months is 2T. However, there are some differences between the two sizes. 24 months clothes are generally made for 18-24 month old babies, while 2T is intended for 2-3 year old kids. Every brand is different, so there may be some variation in the measurements between brands or styles. 24 months clothes have more room for diapers, while 2T clothes have a slimmer silhouette for toilet-trained kids. 24 months clothes are usually found in the baby department, while 2T clothes are in the childrens department. Some brands, such as Gerber, consider both 24M and 2T to be the same size.