P.S. Longer Letter Later is an epistolary novel written by Paula Danziger and Ann M. Martin in 1998. It is a novel in letters and is written as a year-long correspondence between two twelve-year-old girls, Tara (styled Tara*Starr) and Elizabeth. The novel was followed by a sequel, Snail Mail No More.

The novel was developed with Danziger writing as Tara and Martin as Elizabeth. The writing styles of the authors' individual works are reflected in the styles for Tara (whose voice resembles Danzinger's Amber Brown books) and Elizabeth (whose writing is similar to Baby-sitters Club books). In a radio interview, the authors said that as they developed the story together, their own friendship was tested like that of their characters.