What is the longest Harry Potter novel written by J.K. Rowling by word count?

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

Published in 2003, the fifth book contains roughly 257,000 words in its English edition, making it the largest of Rowling’s seven Harry Potter novels by word count. It is also known for its substantial page length, although page totals vary between editions, formats, and countries.

The novel follows Harry’s return to Hogwarts while the Ministry of Magic refuses to accept that Voldemort has returned. Dolores Umbridge is installed as Hogwarts High Inquisitor and then Headmistress, while Harry and other students form Dumbledore’s Army to learn practical defensive magic.

Readers sometimes identify Goblet of Fire or Deathly Hallows as the longest because both are large books and the final novel contains major revelations. However, by English word count, Order of the Phoenix is generally recognized as the longest entry in the original series.