Harry Potter’s middle name in J.K. Rowling’s novels is James.
His full name is Harry James Potter. The middle name honors his father, James Potter, who was a Hogwarts student, a member of the Order of the Phoenix, and one of Harry’s parents. James and Lily Potter were killed by Lord Voldemort when Harry was an infant, leaving Harry with the lightning-shaped scar associated with the attempted murder.
The name becomes especially significant in the later books because Harry’s relationship with his father is complicated. Harry admires James but also learns that James could behave arrogantly toward other students. This contrast helps Rowling present family resemblance as more complicated than simple hero worship.
Harry later gives the name James to one of his sons. His child is named James Sirius Potter, combining his father’s name with the name of Harry’s godfather and closest family friend, Sirius Black.