The Killer is One of 13 (1973, Spain) is a Giallo directed by Javier Aguirre
- Released in 1973
- Production Co: Belén Films/Producciones Internacionales Cinematográficas Asociadas (PICASA)
- Distribution Co: Belén Films (Spain) (all media)
- Directed by Javier Aguirre
- Written by Javier Aguirre, Alberto S. Insúa
- Starring Patty Shepard, Simón Andreu, José María Prada, Trini Alonso, Dyanik Zurakowska
- A widow invites thirteen guests to stay at her rural mansion. She reveals to them that she suspects whoever killed her husband must be one of them. Soon, they too are being murdered one by one.