Sister Stella L. is a 1984 Philippine political drama film co-written and directed by Mike de Leon from a screenplay he co-written with Pete Lacaba and Jose Almojuela. The screenplay was based on and inspired by the life and experiences of Sr. Chayong Battung and Sr. Mary Pilar Versoza and it revolves around a nun becoming politically involved as she took part in a strike where she fought for the rights of the workers. It stars Vilma Santos as the titular nun of the film, Jay Ilagan, Gina Alajar, Laurice Guillen, and Tony Santos Sr.

Initially, Mike de Leon wanted to produce the film by himself. However, because of financial limitations, he was forced to ask Regal Films founder and executive producer Lily Monteverde to join as producer and she agreed. Produced and released by Regal Films on July 11, 1984, the film was a commercial failure but received acclaim when it won ten awards, including Best Picture, Best Actor, Best Actress, Best Screenplay, and Best Director, from the Gawad Urian Awards. It also competed at the 41st Venice International Film Festival for the Golden Lion but lost to Krzysztof Zanussi's A Year of the Quiet Sun.

The film's theme song "Aling Pag-ibig Pa" was selected by the Catholic Mass Media Awards as the best theme song in 1984.