Kylie Jenner And Stassie Karanikolaou -- Double Trouble For Best Friends Day!

What better way to ring in Best Friends Day than to share Kylie Jenner and Stassie Karanikolaou's hot twin takes!

These partners in crime are practically sisters at this point, since they have been proudly sharing their matching moments since middle school ... and there's no sign of them stopping anytime soon!

From sizzling poolside pics to coordinated costumes these ladies love an excuse to snap some pics that might have you doing a double-take!

Get a good look at all their sexy shots together by scrolling through our gallery of Kylie and Stassie's twinning photos!