The Little Mermaid: Ariel's Beginning (also known by the working title, Walt Disney Pictures: The Little Mermaid: Ariel's Beginning, The Little Mermaid III: Ariel's Beginning or The Little Mermaid 3: Ariel's Beginning) is a 2008 animated direct-to-video musical fantasy film produced by Disneytoon Studios, with the animation production being done by Toon City Animation, Inc. and DisneyToon Studios Australia. This film is the prequel to Disney's 1989 animated feature film The Little Mermaid, the third installment in The Little Mermaid trilogy, and the last direct-to-video sequel after John Lasseter took over as chairman for the Disney Animation Division. It is also the first in the chronology of the story running through the series, and it is based on the fairy tale The Little Mermaid by Hans Christian Andersen and The Little Mermaid animated television series which ran for three seasons.

Directed by Peggy Holmes (in her directorial debut), the film's story is set before the events of the original film, when Ariel is still young, and when all music has been banned from the underwater kingdom of Atlantica by King Triton after being heartbroken at his wife's death, and Ariel attempts to challenge this law. Jodi Benson and Samuel E. Wright (in his final film role) reprise their roles as Ariel and Sebastian respectively, while Sally Field voices the film's new villainess, Marina Del Rey. Jim Cummings takes over the role as King Triton, replacing Kenneth Mars, who had been diagnosed with pancreatic cancer.

The film was released by Walt Disney Studios Home Entertainment on August 26, 2008. Though critical reception was improved over its predecessor, the film received mostly negative reviews that criticized the score, while the animation, screenplay, and voice performances were praised.