A letter box is a receptacle for receiving mail.
Letterbox may also refer to:
- Distribution of advertising mail by letter box drop
- Letterboxing (filming), the practice of transferring film shot in a widescreen aspect ratio to standard-width, resulting in a letterbox
- Letterboxing (hobby), outdoor orienteering game
- Letter Box (game show), a 1962 Australian game show
- "Letterbox", a song by They Might Be Giants from their 1990 album Flood
- Letterbox, a 2017 album by Marie Miller
- Letterboxing, a method which mitigates Internet tracking by screen size
See also
- Letterboxd, a social networking site for films
- Party Time (TV series), an Australian game show