I was looking for fairly light-weight cotton socks as it is summer and my feet get so hot. My feet still get hot in these. I'd say they're medium weight (not light, not heavy). I wear a size 10 shoe and they barely fit, but will add they do not slip down which is great. When wearing with tennis shoes, they do not show at all because they are so low cut. Unfortunately, I still need to keep looking for better (cooler) summer socks.