She is wearing Giambattista Valli on the cover that was photographed by Michael Thompson and styled by Lori Goldstein. (source)
Click here to view last year cover featuring Dakota Johnson, here to view 2013 covers featuring Taylor Swift, here to view 2012 cover featuring Blake Lively, here for 2011 cover with Katy Perry, and here for 2010 cover with Keira Knightley.
The cover was photographed by Gui Paganini. (source)
Click here to view last year cover featuring Magdalena Jasek, Camille Rowe Pourcheresse and Ysaunny Brito, here to view 2013 cover featuring Aline Weber, here to view 2012 cover featuring Patricia Van Der Vliet, here for 2011 cover with Fabiana Mayer, and here for 2010 cover with Caroline Trentini.
The cover by Steven Pan is a reprint from Glamour US March 2015. (source)
The cover was shot by Marcin Tyszka. (source)