S may refer to:
- S, also known as Esu, a Boys' Love Genre Light Novel series by Saki Aida and Chihara Nada.
- S, a Shoujo tennis manga by Setona Mizushiro.
- S., a novel by John Updike.
- S, a novel told via marginal notes in another novel, by J. J. Abrams and Doug Dorst.
- S, a short-lived K-Pop group.
- The page on One-Letter Titles.