It is our experience that Roxy clothing sizing can be somewhat confusing.   Some items are labeled as Misses, Womens, or  Juniors.   The Roxy clothing line was an offshoot of Quicksilver for Junior (teenage) girls.  

The shirts are made of an exeptionally soft 100% cotton, which can shrink a bit with repeated washing and drying.   We strive to offer M, L, and XL sizes, to ensure clothing that still fits well after years of washing.   As a Mom with two fast growing girls, I recommend buying an item a size or two larger, so they get as much wear out of it as possible before they out grow it.  :)   Roxy shirts are so comfortable that my daughters love to sleep in them!