Which Harry Potter novel by J.K. Rowling has the greatest word count?

Harry Potter and the Order of the Phoenix is the longest Harry Potter novel by word count.

Published in 2003, Harry Potter and the Order of the Phoenix contains approximately 257,000 words in its English edition, making it the longest of the seven main books. It follows Harry’s fifth year at Hogwarts and introduces Dolores Umbridge as the Ministry-appointed Defence Against the Dark Arts teacher.

The novel also develops the Order of the Phoenix, a secret organization opposing Voldemort, and shows the Ministry of Magic denying that Voldemort has returned. Harry’s recurring dreams and his connection to Voldemort become especially important.

The longest book is not the same as the longest film. The film adaptation substantially condenses the novel, as all the movies do. Word counts can vary slightly by edition and counting method, but Order of the Phoenix is consistently identified as the series’ longest book.