Trailer may refer to:

In transportation
  • Trailer (vehicle), an unpowered vehicle pulled by a powered vehicle
    • Bicycle trailer, a wheeled frame for hitching to a bicycle to tow cargo or passengers
    • Full-trailer
    • Semi-trailer
    • Travel trailer, or caravan, a type of recreational trailer designed to provide sleeping space
  • Construction trailer, temporary accommodation for offices and building materials storage on construction sites
  • Semi-trailer truck
  • Mobile home, a housing unit built in factories, rather than on site
  • Portable classroom, a temporary classroom for schools with insufficient building capacity
In computing
  • Trailer (information technology), data appended to a main block of data to facilitate its processing
In films and video
  • Trailer (book), a short video for marketing a book
  • Trailer (film), an advertisement, usually in the form of a brief excerpt or string of excerpts, for a new film
    • Teaser trailer, a truncated version of a theatrical or film trailer
In music
  • Trailer (album), a 1994 album from the Northern Irish musical group Ash