Letter, letters, or literature may refer to:
- Letter (alphabet), a character representing one or more of the sounds used in speech; any of the symbols of an alphabet.
- Letterform, the graphic form of a letter of the alphabet, either as written or in a particular type font.
- Rehearsal letter in an orchestral score
- Letter (message), a form of written communication
- Letters, the collected correspondence of a writer or historically significant person
- Pauline epistles, addressed by St. Paul to various communities or congregations, such as "Letters to the Galatians" or "Letters to the Corinthians", and part of the canonical books of the Bible
- Maktubat (disambiguation), the Arabic word for collected letters
- The letter as a form of second-person literature; see Epistle
- Open letter, a public letter as distinguished from private correspondence
- Letter to the editor, a letter sent to a newspaper, magazine, or online publication by one of its readers and meant to be published
- Encyclical letter in the Catholic Church
- Apostolic letter (litterae apostolicae), a type of ecclesiastical letter in the Catholic Church
- Letter (paper size), paper conventionally sized for letter-writing
- Letters, an obsolete synecdoche for literacy; e.g. "He knows his letters"
- Literature as in Letters, Arts and Sciences
- Varsity letter, an award given in the U.S. for interscholastic or intercollegiate merit in a sport or other activity such as band or orchestra