Yes. Very VERY late in the game you find out about Riley (earlier if you look through Ellie's stuff in one part). Though, Ellie doesn't say that she likes girls(or boys, xD though, there is a funny bit with a "dude mag").
Ellie: xD "WOW! How would he walk around with that thing?!"
Though, she calls Riley her best friend, not her girlfriend. That said, as you may have guessed, even if she really did want to be with Riley like that, their time together got cut short pretty much right after she kissed Riley.
