Wonderful costume that I’ll wear to comic con this year. The material is stretchy, but not overly so, for reference, I’m 5ft, 2 inch, 140lbs, 34b, 27 inch waist, ordered an xs and it fits like a glove. I’m very slender on top, so if you’re a little top heavy, you’ll have to size up. Sleeves fit is very tight if arms are not slender. I’ve been wearing Badinka costumes for years and I’m always a size xs.