Guillermo Ríos (born August 8, 1956, Mexico City, Mexico) is a Mexican actor, screenwriter, and director who studied theater at the Universidad Veracruzana and the Escuela de Arte Teatral del Instituto Nacional de Bellas Artes, and trained under Milton Katselas in Los Angeles. He began as a stage actor and playwright, earning a "Mérito Universitario" medal from UNAM for his play El día que México ganó el mundial. He later expanded into television writing, contributing to telenovelas and the HBO series Capadocia, and co-wrote the hit comedy Instructions Not Included (2013). He has been active for over 40 years with credits in more than 35 feature films. His notable film credits include Clear and Present Danger (1994) (Harrison Ford, Andy Garcia), The Falcon and the Snowman (1985) (Brad Davis, Sigourney Weaver), Old Gringo (1989) (Paul Newman, Chazz Palminteri), Let's Get Harry (1986) (James Brolin, Karen Black), Primal Force (1999) (Jean-Claude Van Damme, Jason Patric), Innocent Voices (2004) (Salma Hayek, Luis Guzmán), Under the Same Moon (2007) (Lukas Haas, Selene Unternberg), Che: Part One (2008) (Benicio Del Toro, Rodrigo Santoro), Sleep Dealer (2008) (Scott Speedman, Monica Del Carmen), Colombiana (2011) (Zoe Saldana, Michael Vartan), Get the Gringo (2012) (Mel Gibson, John Malkovich), Colosio (2012) (Daniel Giménez Cacho, Regina Orozco), No Returns Accepted (2013) (Eugenio Derbez, Zoe Saldana), and The 4th Company (2016) (Diego Boneta, Christian de la Campa). He also wrote and directed Perras (2011) and the 2025 series Unspeakable Sins.