Which Harry Potter novel by J.K. Rowling is the longest in the original UK editions?

Harry Potter and the Order of the Phoenix is the longest Harry Potter novel in the original UK editions.

The fifth book in J.K. Rowling’s series was published in the United Kingdom in 2003. Its first UK hardcover edition contains 766 pages, making it longer than the other six main novels in their original British editions.

The story follows Harry’s fifth year at Hogwarts, the Ministry of Magic’s denial that Lord Voldemort has returned, and the formation of Dumbledore’s Army. Dolores Umbridge becomes Hogwarts’ High Inquisitor and later High Professor, while the Order of the Phoenix reorganizes to oppose Voldemort.

Page counts vary by format, publisher, typography, and language, so the claim refers specifically to the original UK editions. The US edition is also notably long, but different page layouts mean editions should not be compared without identifying their market and format.