Polygon states that they were told that Kalos Pokémon will not have Mega Evolutions
http://www.polygon.com/2013/9/19/47...ches-up-the-classic-story-formula-to-focus-onBut only specific Pokemon have Mega Evolutions; older Pokemon like Mewtwo, Lucario and the Generation One starters will have Mega Evolutions, but Pokemon newly introduced in X and Y will not.