Which Harry Potter novel by J.K. Rowling is the longest by page count in its original English editions?

Harry Potter and the Order of the Phoenix is the longest Harry Potter novel by page count in its original English editions.

The fifth novel was published in 2003 and has 766 pages in its American hardcover edition. The British hardcover edition has 766 pages as well, although page counts can differ between formats, printings and languages. That is why comparisons should specify the edition rather than treating every published copy as identical.

The story follows Harry’s fifth year at Hogwarts and introduces the Ministry-appointed teacher Dolores Umbridge. It also develops the secret student group Dumbledore’s Army and the prophecy linking Harry with Lord Voldemort. The novel’s length is often compared with Goblet of Fire, which is substantial but shorter in its standard English editions.