I bought this set for my 15 month old to wear for Halloween Pajama day at daycare. She's a little on the larger side in the 55th percentile, so the sleeves were a little extra snug even after sizing up. I did pull and stretch the sleeves a little bit and that helped to loosen them up so that she wouldn't be tugging at them all day. It's not a shirt I have her wear a lot because the sleeves are a little more snug than she is comfortable with, but the pants fit great!