The Warning (Spanish: El Aviso) is a 2018 Spanish thriller film directed by Daniel Calparsoro and based on the novel of the same name by Paul Pen. The screenplay was adapted by Jorge Guerricaechevarría and Chris Sparling. It was produced by Morena Films. The Warning was shown at the 2018 Miami International Film Festival and premiered on Netflix in July 2018. The film received mixed reviews from critics.