Neville Longbottom is a pure-blood Gryffindor student in Harry's year, described as round-faced and "short and plump and blond". Throughout the series, he is often portrayed as a bumbling, disorganised character and a rather mediocre student, though he is highly gifted at Herbology. He is often teased and hexed by other students, such as Draco Malfoy, Gregory Goyle and Vincent Crabbe. His parents, Frank and Alice Longbottom, were prominent Aurors and Order of the Phoenix members until they were tortured and permanently incapacitated by a group of Death Eaters led by Bellatrix Lestrange; Neville was subsequently raised by his paternal grandmother, Augusta. Neville plays a minor role in the first four books, but Rowling wanted him to perform an act of bravery in Philosopher's Stone, in which Neville "finds true moral courage in standing up to his closest friends — the people who are on his side" towards the climax.
According to Rowling, Order of the Phoenix "was a real turning point for Neville" due to the bigger role he played therein. His magical abilities improve dramatically during D.A. meetings, and Harry comes to understand him on a deeper level after he and his friends learn about the fate of Neville's parents at St Mungo's. Neville participates in the battle in the Department of Mysteries, in which he accidentally breaks the prophecy about Harry and Voldemort. Dumbledore, to whom it was originally made, explains that it concerned "the Chosen One", a wizard who would have the power to vanquish Voldemort and who would be born "as the seventh month dies" to "parents who have defied the Dark Lord thrice"; thus could refer to either Neville, who was born on 30 July 1980, or Harry, who was born a day later. Neville is also one of the few D.A. members to participate in the battle of the Astronomy Tower in the climax of Half-Blood Prince.
With Hogwarts at the mercy of new headmaster Severus Snape and the Carrows in Deathly Hallows, Neville reforms Dumbledore's Army with Ginny and Luna, and spends much of his seventh year as the group's interim leader in Harry's absence, helping students who are tormented under the new regime. Neville reveals to Harry that he had suffered beatings by the Carrows and was forced to go into hiding in the Room of Requirement to avoid Azkaban or death. During the Battle of Hogwarts, Neville uses his knowledge of Herbology to help ward off the attackers, and later helps Oliver Wood carry the body of Colin Creevey. When Voldemort returns with Harry's apparently lifeless body, Neville breaks free from the crowd to attack Voldemort. However, he is immobilised by Voldemort's Full Body-Bind curse, after which the Sorting Hat is placed on his head and set on fire. Neville later breaks free of the curse, pulls Godric Gryffindor's sword out of the sorting hat (a feat that can only be achieved by a true Gryffindor) and decapitates Nagini with the sword, thus destroying the final Horcrux. In the ensuing conflict, he assists Ron in taking down Fenrir Greyback. After the battle is won, Neville is surrounded by a group of admirers.
In the epilogue of Deathly Hallows, Neville returns to Hogwarts as its new Herbology professor, due to his love of the subject, and shows off his D.A. Galleon to many admiring students and tells them about his adventures. Rowling revealed in October 2007 that Neville married Hannah Abbott, who then became the new landlady of the Leaky Cauldron. They live over the pub, which Rowling believed readers would find "particularly cool." In the film, Neville's love interest is Luna Lovegood, and they are seen together at the end.
Neville is portrayed by Matthew Lewis in the Harry Potter films.
IGN listed Neville as their sixth top Harry Potter character, calling him the "quintessential dimwit-turned-hero".