Luna Lovegood is a Ravenclaw student, introduced in Harry Potter and the Order of the Phoenix. She is one year below Harry, and is often known at Hogwarts as her nickname, Loony Lovegood.
The reason why she has this nickname is because she sees the world in a different way to others. After all, she is a Ravenclaw hence being creative.
She lives in a small shack with her father, as seen in the Deathly Hallows.
In the Order of the Phoenix, she is introduced when Harry and his friends take the carriage to Hogwarts, when Harry sees an odd creature, pulling it. Nobody could see it except Harry and Luna.
"You're not going mad - I can see them too. You're just as sane as I am" Was Luna's first line to be said.
In the movies, she is often seen reading a book called The Quibbler, and wore the glasses with it for nearly the whole of Harry Potter and The half blood prince. She also often talks about creatures called nargles, which remain a mystery, as they never get seen in person.
Evanna Lynch is the actor to play as Luna.