SARAH A I am wearing these socks right now! They run a bit smaller than usual. I wear 7.5 and the M fits just right. My mom wears a 9.5 and wishes she had gotten the L.

CAROLA O I can only speak for size medium of these socks. They fit me perfectly and I wear a 9 or 91/2 womens shoe.

DAVID V S: 4.5-7 M: 7.5-9.5 L: 10.5 -11.5

MICHELE F The packaging says for women S (4-6.5), M (7-9.5), L (10-12.5). I discovered these socks a couple years ago and they are awesome! Very comfortable and more durable in my experience than Smartwools. I have yet to have a pair wear out and they come with a lifetime guarantee!