I  wear an extra small (XS) and inside this vest it read XS (small), however it measured exactly the size small (S) I also have - which is too big for me.  I returned it for a refund because if I ordered another it was likely that I would get another size small no matter what it says inside. Too bad as I really would like to have a size XS.  Other than that it is just perfect.  Nice and warm for early spring, fall and winter.  Well made.