i am a size 6 and ordered 6 1/2 because it looks its going to be tight BUT 6 1/2 is a bit roomier even with hanes socks. So order your true size even if you're planning to wear sports socks. Still even when its a bit bigger, I DON'T want to return and order a size smaller since it looks so new and well-made, i may end up with a damaged pair.  So I'm keeping it but don't get me wrong... the comfort of the foot bed is so unlike any other rain boots. It feels so cushiony and can walk without hurting my feet even with the heel height.  You don't feel the strain on your foot, you just feel taller.  And the its slim design doesn't make you feel like you're wearing a rain boot. Go grab a pair while its still available, you will not find a better looking rain boot. Its by far my most comfortable rain shoes ever. I am even tempted to wear it even when its not raining, its that fabulous. I am 5 ft. tall, 110 lbs and size 6 in shoes.