In literature, film, and other such arts, an unreliable narrator is a narrator who cannot be trusted, one whose credibility is compromised. They can be found in fiction and film, and range from children to mature characters. While unreliable narrators are almost by definition first-person narrators, arguments have been made for the existence of unreliable second- and third-person narrators, especially within the context of film and television, but sometimes also in literature.

A frame story is a literary technique that serves as a companion piece to a story within a story, where an introductory or main narrative sets the stage either for a more emphasized second narrative or for a set of shorter stories. The frame story leads readers from a first story into one or more other stories within it. The frame story may also be used to inform readers about aspects of the secondary narrative(s) that may otherwise be hard to understand. This should not be confused with narrative structure. A notable example is The Decameron.