i dont think she'd fit into any of the other houses, maybe hufflepuff, but not gryffindor or slytherin

katie, hufflepuff

i think she was played into ravenclaw because she thinks about things a lot. she doesn't think about them from everyone's point of view, but she knows what she believes and is very intelligent about everything she cares about, if that makes any sense.
-leah, hufflepuff.

Very agreed.

Em, Gryffindor

Luna is a Ravenclaw in every sense of the word. She's obviously intelligent, and and honestly doesn't care what others think of her often unusual theories and beliefs. She's very independant and self-confident, and every decision she makes is based on a rational thought process. As strange as she is, I can't see her anywhere but my House. ;)

Elizabeth
Ravenclaw

Probably to show inter-house unity. And I'm sure Luna will play a big part in HBP and B7.

Rather than repeating what everyone said, I'll just say that I agree with all the above comments! I think Luna is one of the most intelligent students at Hogwarts because she thinks more about life rather than materialistic things or grades, which is very mature in a kid.

She's intelligent, creates her own belief system and sticks to it, and isn't afraid to be an individual. And there's also the fact that JKR needed to throw in a main Ravenclaw character that wasn't a crying brat. :P

I at first questioned why she was in Ravenclaw as well. I think because she values Intelligence highly, above everything else she was placed in Ravenclaw. Even if she isn't really all that smart. I see her as having average intelligence.

- Liz, Hufflepuff