Which Harry Potter novel is the longest in the original English series?

Harry Potter and the Order of the Phoenix is the longest novel in the original English Harry Potter series.

The fifth book was published in 2003 and contains 766 pages in its UK hardback edition. It is also often described by word count as the longest of the seven novels, though exact totals vary by edition and counting method. The story follows Harry’s fifth year at Hogwarts and the Ministry of Magic’s refusal to accept that Voldemort has returned.

The novel introduces Dolores Umbridge as Hogwarts High Inquisitor and features the formation of Dumbledore’s Army. Harry also experiences increasingly important visions and learns more about the connection between himself and Voldemort.

The American film adaptation was released in 2007. Despite the novel’s length, the movie is one of the shorter entries in the film series, illustrating why page count and screen time should not be treated as equivalent measures.