I'm 5/6' 148 lbs and ordered a medium.  It is perfect.  Beautiful bright green and material is a medium weight, soft, gauze like.  Length is long; past hips, which I hoped for.  Fit is loose, and long enough so I'm washing it in cold and will put it in d  dryer for a little shrinkage.  Then I'll always wash in cold and hang to dry.  I like it so much I'm gonna order another.  Got it in a couple days too.

update:  washed in cold and dried in dryer; got shrinkage and it is perfect.  Really like material.  Has a slightly fluffy look.  This green is beautiful.  Have ordered the mustard/yellow.