Bionicle: Mask of Light, stylized as BIONICLE: Mask of Light — The Movie, is a 2003 computer-animated science fantasy action film based on the Bionicle toyline by Lego, and particularly serves as a direct adaptation to the latter half of the toyline's 2003 narrative. Set in a universe filled with bio-mechanical beings allied with classical element-themed tribes, the story follows two friends from the fire-based village of Ta-Koro on a quest to find the owner of the Mask of Light, a mystical artifact that can potentially defeat Makuta, an evil entity threatening the island.

The project was first proposed in 2001, during the original run of the Bionicle toyline. Lego contacted multiple writers for the project, including original Bionicle contributors Bob Thompson and Alastair Swinnerton, and Hollywood writers Henry Gilroy and Greg Weisman. Production began in 2002, taking approximately a year to complete. A major part of the graphical design was adjusting the characters so they could work in human-like ways while still resembling the original toys. The music was composed by Nathan Furst, who used orchestral and tribal elements to create the score. Voice casting was handled by Kris Zimmerman, and the voicework was done with the setting and mythos of Bionicle in mind.

Multiple studios were involved in the development and distribution of Mask of Light: it was co-produced by Lego and Create TV & Film, developed by Creative Capers Entertainment and CGCG, and post-production was handled by 310 Studios and Hacienda Post. It was released on September 16, 2003 on home video and DVD by Buena Vista Home Entertainment under the Miramax Home Entertainment label. Upon release, the film reached high positions in VHS and DVD charts, and received generally positive reviews from journalists. Mask of Light was followed by two prequel films, Bionicle 2: Legends of Metru Nui in 2004 and Bionicle 3: Web of Shadows in 2005, and a stand-alone sequel, Bionicle: The Legend Reborn, in 2009.