My twins usually wear size 12. When I received this Jammie set, sized XL, it was a labeled as a 14/16, which I thought might be too big, but fit totally perfectly ????!! So, I would say, and this goes for much of the Calvin Klein products I have ordered over the decades of my life, it isn’t unusual for me to say.. size ???? ⬆️ one size on this set!! The top is fairly thin, but it’s super cute. and works out well for cold summer nights in the mountains by our camper, cool spring & fall evenings, and winter in the house when it’s fairly warm, but you wanna be cozy. My daughter wearing this set is 5 feet even & 97 lbs. she has a slim, lean, dancer’s build. The quality is there, but like I said, it’s a tad thin, which potentially could make it see through up top, but because of the darker color I got, and the fact that it’s my 12 year old child wearing it, who is still quite small, no concerning issues, just making note of it. That might not be the same for larger bodies, I can only speak from our standpoint here. (We picked the color with the dark blue, thermal too. That color helps.) Size up one, and it should fit like a glove, and is worth the sale price of $16 and change, for sure! A nice gift, and nobody would expect that you paid so little for an authentic, Calvin Klein sleep set! Worth the $, but runs a little bit small. 4.25 stars! ⭐️⭐️⭐️⭐️ + 1/4 ** I hope my review has been helpful ????.**