I first ordered this dress in my usual size - small. I am 5'10"-ish and normally a size 4. The small was tight all around, especially in the arms. Mine are long and somewhat muscular, but not in any way big. I sent the dress back and then a few weeks later decided to try a medium. It was only slightly bigger, still so tight I almost couldn't believe it. I feel neither adventurous nor patient enough to try a large. I have never worn a large in anything, and I suspect that would be too small as well. Wtf?