Bionicle 2: Legends of Metru Nui is a 2004 computer-animated science fantasy action film and the second film based on Lego's Bionicle toy line. It is a prequel to the first film, Bionicle: Mask of Light. This film follows the 2004 storyline and was created using Lego elements from the Bionicle series. It is also the second of the two films in the franchise to be given a rating by the MPAA. It was released on DVD and VHS on October 19, 2004, by Buena Vista Home Entertainment under the Miramax Home Entertainment label.

In this film, Vakama recalls events that took place long before the classic Bionicle stories at Mata Nui, during which he, along with his friends Nuju, Matau, Onewa, Whenua, and Nokama were chosen to be the new Toa of the island of Metru Nui. To save the city, they must prove themselves worthy Toa, find their mask powers, and protect the "Heart of Metru Nui", but they also find themselves caught up in the schemes of the evil Makuta.

The film received mixed reviews, with some noting the filling in of plot holes from the previous film. The series continued to be noted for its visual effects and musical score. It was followed by a sequel, Bionicle 3: Web of Shadows.