I usually wear a size 8-10 but ordered the large. While it's comfortable, I probably should have gotten a medium because it does run a bit large. It's very long which is fab for tall girls. I took it to the tailor to have a few inches taken off and had a small amount of the armhole stitched up as the armholes are wide open. You can do this at home in a few minutes yourself. I purchased the navy which is not as dark as the photo, where it almost looks black. There is some rusty-red in the pattern too which also doesn't show. It is a pretty dress and I'm sure I'll have years of wear from it as the fabric is nice and silky and it's well made.