Minsa'y Isang Gamu-gamo (English: Once a Moth) is a 1976 Filipino protest drama film directed by Lupita Aquino-Kashiwahara from a story and screenplay written by Marina Feleo-Gonzales. It stars Nora Aunor, Jay Ilagan, Gloria Sevilla, and Perla Bautista. Set near Clark Air Base in Pampanga, the film depicts the lives of two families affected by the American military presence in the Philippines.

Premiering at the 2nd Metro Manila Film Festival, the film won Best Story for Feleo-Gonzales. In 2018, the film was digitally restored by the ABS-CBN Film Restoration Project with a subsequent theatrical premiere at the Cinema One Originals festival of that year.

It was the first important film to address the subject of the American military presence in the Philippines during the Bases era. The film ultimately argues for the closure of these facilities.