Slayer can refer to:
- MAP21 of Final Doom: The Plutonia Experiment.
- The Doom Slayer, a title given to the protagonist of Doom (2016) and Doom Eternal.
- SlayeR (WAD), a 2001 map set by Richard Wiles which was considered by Doomworld as one of the Top 100 WADs of All Time.
- Simon Judd (SlayeR), the developer of the editing utilities SLumpEd and SLADE.