My daughter wears a size 6X usually.  We ordered the Large and they are a little too big on her.  But because they are leggings they hugged her body and stay on with room to grow at the bottom.  The fabric was super soft and comfortable.  The leggings are thin, but generally that is what you want when you purchase leggings.  I needed the color orange for a school play, and that is an impossible color to find in the stores.  So while this was a little expensive, it fit exactly what I needed.