Director Mike Newell was not aware that Alan Rickman wore black contact lenses for the role of Snape until one day when he was complimenting him on the amazing shade of his eyes. Rickman leaned over and popped one of the lenses out.
During the course of filming, Daniel Radcliffe matured a lot physically. In an interview, Mike Newell remarked "I've just been working on a scene which we shot in our first week, and Dan still looks like the little kid that he was in Sorcerer's Stone. Now, eleven months later, he doesn't look like that at all."
Mike Newell only received $1 million to direct (whereas Chris Columbus received $10 million, plus a percentage of the gross, to direct Harry Potter y la Piedra Filosofal (2001)).
While filming his scenes as Professor Dumbledore, Sir Michael Gambon wore street clothes under his flimsy costume. He also kept his cigarettes tucked into his socks.
Final Harry Potter movie to feature scenes filmed at the University of Oxford. Oxford inspired much of the architecture of Hogwarts, including the Great Hall.