I have noticed with Vionics that they run large. Definitely order a size down. I had to return these because I forgot about the size thing. Truthfully, though, I wasn't in love with the style. That's a personal opinion but they looked better on the computer screen than in person from my point of view so I didn't reorder them in the right size. I have several pairs of Vionics and ordered a different style after these as well. They have pretty much cured my plantar fasciitis. I can't wear completely flat shoes anymore. The arch support with this brand takes a little getting used to at first but then they make all the difference and I can wear them all day.