A teaser trailer is a truncated version of a theatrical trailer intended to entice the audience about an upcoming movie and to begin hype on major films.

Teaser trailers, unlike the typical theatrical trailer, are usually very short in length, usually under 30 seconds. The purpose of the teaser trailer is not to show a bunch of out-of-context clips in order to give the audience an understanding about the movie's plot or theme, but rather to let them know that the movie is coming up in the near future, and to add to the hype of the upcoming movie event. Teaser trailers are often made while the film is still in production or being edited and as a result they may feature scenes or alternate versions of scenes that are not in the finished film. Teaser trailers today are increasingly focused on internet downloading and the convention circuit.

Teaser trailers are usually only made for big-budget and popularly themed movies. Recent examples of major motion picture events that used teaser trailers to gain hype are the Lord of the Rings trilogy, the new Star Wars films and the Spider-Man films. An early example of the teaser trailer was the one for the Superman film by Richard Donner when as the film was already nearly a year late was designed to re-invigorate interest in the release.

Teaser trailers are usually shown among other movie previews, and appear months before the longer and more detailed theatrical trailer does. Some teasers have been known to appear as long as nine months to a year prior to the movie's final release date. They are usually regarded as a bonus to cinema goers. However, in the case of the teaser trailer for The Phantom Menace that was attached to the film 'The Siege', it was reported that the majority of the audience walked out after the trailer had screened.

Most DVD versions of these movies will have both their teaser and theatrical trailers in their bonus sections.