| Release Date | 01 September 1937 |
| Tagline | Jeanette MacDonald Is The Luminous Singing Spy! |
| Genre | History, Musical, Romance, Action |
| Country | USA |
| Filming Locations | Alabama Hills, Lone Pine, California, USA |
| Language | English |
| Sound Mix | Mono |
| Color | Black and White |
| Film Type | Feature |
| Film Class | Musical Drama |
| Niche Genre | Spy Film |
| Tones | Elegant, Lavish |
| Tags | Dance [art], Espionage, Love, Noble, Romance, Songwriter |
The Firefly is a 1937 musical film starring Jeanette MacDonald, Allan Jones. The film is an adaptation of the operetta of the same name by composer Rudolf Friml and librettist Otto A. Harbach that premiered on Broadway in 1919. The film used nearly all of the music from the operetta but jettisoned the plot in favor of a new storyline set in Spain during the time of the Emperor Napoleon I. It added a new song, "The Donkey Serenade", which became popular, as was one of the Friml songs, "Giannina Mia", both of which were released on 78 r.p.m. gramophone records.