Neville Longbottom is a fictional character in J. K. Rowling's Harry Potter book series. He is described as a round-faced Gryffindor student in the central character Harry Potter's year. Throughout the series, Neville is often portrayed as a bumbling and disorganised character, and a rather mediocre student, though he is highly gifted at Herbology. However, the character's personality appears to undergo a transition after he joins Dumbledore's Army in Harry Potter and the Order of the Phoenix. The encouragement he receives gives him confidence in his magical abilities, turning him into a more competent wizard. Eventually, Neville becomes the leader of Dumbledore's Army during Harry, Ron and Hermione's absence searching for Horcruxes. Neville is instrumental in the downfall of Lord Voldemort and eventually destroys the final Horcrux, which allows Harry to defeat The Dark Lord once and for all. Neville is portrayed in the film adaptations by Matthew Lewis.

In J. K. Rowling's Harry Potter series, magic is depicted as a supernatural force that can be used to override the usual laws of nature. Many fictional magical creatures exist in the series, while ordinary creatures sometimes exhibit magical properties. Magical objects are also described. Witches and wizards refer to the rest of the population, who are generally unaware of magic, as "Muggles" in the United Kingdom and "No-Maj" in the United States.