Guillermo Ríos (born August 8, 1956, in Mexico City) is an acclaimed Mexican screenwriter and actor, whose writing has brought to life stories of great emotional impact and international success. He is best known for co-writing the global phenomenon Instructions Not Included (2013) with Eugenio Derbez, a film that masterfully blended comedy and drama, becoming the highest-grossing Spanish-language film ever in the United States at the time of its release. The success of this screenplay led to the French remake Two is a Family (2016), solidifying his ability to create universal narratives. Prior to this, Ríos had already demonstrated his skill in exploring complex themes with the ensemble film Perras (2011), a raw and incisive portrayal of female adolescent life. In addition to his writing, Ríos also occasionally appears as an actor, showcasing a deep understanding of the cinematic craft from both sides of the camera.