I am so pleased with this costume! I am 5'8" and 150 lbs, so I usually am between an 8 and a 10 dress size. I ordered the medium. I was a little worried it wouldn't be long enough, but it fits me great. It's a little snug in the rear, but they were like that in the show. I am a little bit curvy with hips on the bigger size and this is a very flattering fit for that body type. The pants are a little short on me, but with black boots it'll look fine. This is a great custume for the girl who loves TNG and doesn't like to go the slutty route on Halloween.