She is wearing Louis Vuitton Spring Summer 2015 on the cover that was photographed by Kerry Hallihan. (source)
Click here to view last year cover featuring Katie Holmes, here to view 2013 covers featuring Rihanna, here for 2012 cover with Mary-Kate and Ashley Olsen, here to view 2011 covers featuring Gwen Stefani and here for 2010 covers featuring Chloe Sevigny.
The cover was shot by Xevi Muntane and Ava is wearing Balenciaga. (source)
Gregory Harris photographed the Spring appropriate cover with styling by Tony Irvine. (source)
The cover was shot by Ram Shergill. (source)
The cover was snapped by Matthias Vriens-McGrath. (source)
Click here to view last year cover featuring Hayden Panetierre, here to view 2013 cover featuring Zooey Deschanel, here to view 2012 cover featuring Holly Willoughby, here for 2011 cover with Beyonce, and here for 2010 cover also with Holly Willoughby.
The cover by Jan Welters is a reprint from Marie Claire US February 2015 with styling by Alison Edmond. (source)