A letter game involves the exchange of written letters, or emails, between two or more participants. The first player writes a letter in the voice of a newly created character; in this first letter the writer should establish her own identity and that of her correspondent, should set the scene, and should explain why she and her correspondent must communicate in written fashion. In subsequent letters plot and character can be developed, but the writers should not talk about plot outside of the letters and the characters should never meet. Letter games can be a writing exercise or a role playing game.

Novels written using or inspired by this type of letter game include Sorcery and Cecilia, by Patricia Wrede and Caroline Stevermer, and Freedom and Necessity, by Steven Brust and Emma Bull.