Lilac Time is a 1928 American synchronized sound romantic war film directed by George Fitzmaurice and starring Colleen Moore and Gary Cooper. While the film has no audible dialog, it was released with a synchronized musical score with sound effects using the sound-on-disc Vitaphone process. The film is about young American aviators fighting for Britain during World War I who are billeted in a field next to a farmhouse in France. The daughter who lives on the farm meets one of the new aviators who is attracted to her. As the flyers head off on a mission, the young aviator promises to return to her.

Lilac Time was produced by John McCormick (Moore's husband), and distributed by First National Pictures. The silent film "adaptation" by Willis Goldbeck is based on a 1917 Broadway play written by Jane Murfin and actress Jane Cowl. Though some sources erroneously cite the play as having been based on a novel by Guy Fowler, the reverse is true: Fowler novelized the Goldbeck adaptation for the popular line of Grosset & Dunlap Photoplay Editions, also drawing upon text and dialogue of the play itself. Lilac Time offers several phases, beginning with slapstick comedy elements, becoming an intense romantic film, then segueing into a spectacular aerial showdown. This was followed by a duel in the sky between Cooper's character and the "Red Ace" before returning to romantic complications.