I initially wear a men's size 12 in almost every other shoe, but listened to the reviews and ordered a 11.5 for fear that 11 would be too small. When I first tried them on they definitely fit, but were a bit loose. I considered returning them for 11 but then found that the insoles that came with the shoes are ridiculously flimsy with no support. So I put in my extra set of SuperFeet Greens and boom, better support gave me that little extra comfort I was looking for. :)