I bought this jacket to go over a plain black sheath dress for an interview instead of buying a new suit.  It looked great. I normally wear a size small top and about a 6/8 in dresses but I ordered the Large here. It was just slightly too tight but a bigger size would have been too big maybe and I didn't have enough time to exchange before the interview. It worked because the jacket is so stretchy and I think I left it open anyway. I'd consider buying again in a different color - I might get the XL though just to see if it fits better.