Loved these so much that we ordered a second pair! And then a third! My 11 month old wears a medium and weighs 24 pounds, just in case that helps anyone. They fit her snugly, but I think that’s good to prevent leaks. She loves that she gets to wear her “chonies” instead of a diaper if she goes in the potty and I think it’s partly because of the comfort and fun prints that these trainers provide.