Katy received the prizes for best video, for "Dark Horse," and best look. She did not attend the ceremony.
Boy-band One Direction collected three awards, while Ariana Grande and 5 Seconds of Summer each picked up two.
Here are the winners:
Best Song Ariana Grande -- "Problem" ft. Iggy Azalea
Best Pop One Direction
Best Female Ariana Grande
Best Male Justin Bieber
Best Live One Direction
Best New 5 Seconds of Summer
Best Video Katy Perry -- "Dark Horse ft. Juicy J"
Best Rock Linkin Park
Best Alternative Thirty Seconds to Mars
Best Hip Hop Nicki Minaj
Best Electronic Calvin Harris
Biggest Fans One Direction
Best Look Katy Perry
Best Push 5 Seconds of Summer
Best Song with a Message Beyoncé, "Pretty Hurts"