I originally bought this dress in a medium, but found it a bit too tight and clingy for my taste in this style of dress. For reference I am 5'5", 130# with a pretty average build. Not as streamlined as I was 20-30 years ago, though, so if you're the same stats but in whip-shape, or you DO prefer fits-like-glove, then I'd say this fits true to size and you're safe going that route. I re-ordered it in a large, and am extremely pleased. The hang is more flapper-straight and gives me more wiggleSee full review