The middle name of J.K. Rowling’s fictional character Hermione Granger is Jean.
Hermione Jean Granger is one of the three central characters in the Harry Potter novels. She is introduced as a highly knowledgeable first-year student at Hogwarts and becomes Harry Potter’s and Ron Weasley’s closest friend. Her intelligence, preparation, and persistence repeatedly help the group solve problems and survive dangerous events.
The name is revealed in later supplementary information rather than being a major plot point in the early novels. Hermione is a Muggle-born witch, meaning that both of her parents are non-magical people. Rowling chose the first name Hermione partly from Shakespeare’s The Winter’s Tale, while the character’s family background and identity are developed through the series.
Jean is sometimes mistaken for Joanne because Rowling’s own birth name is Joanne. It is also easy to confuse Hermione’s middle name with actor Emma Watson’s name or with names belonging to other Harry Potter characters. The canonical character name is Hermione Jean Granger.