I'm usually a medium in outdoorsy brands as I'm 5'9". Ordered a M initially. It was a great length until I washed it (washed only, did not dry) and it shrunk up a little. Thanks to Backcountry's AWESOME return policy, I returned the M and ordered a L and it is a great length. As far as a fit, you can't really go wrong since it's elastic and loose fitting. It's a great dress, definitely my new favorite!