The third Harry Potter film isn't out until 4 June next year, but the trailer is here now and most of you love it.
The Prisoner of Azkaban has a new director in Alfonso Cuaron, and the new look he's given the film is popular.
Kristina, 12, from the US said: "Very spooky and much, much better. The singing is different, but kind of cool. Great job! I can NOT wait."
Jenny, 12, from Surrey said: "It's great! The only problem is there's not very much Ron!"