It is loosely based on true events from a 1991 Vallecas case in which Estefanía Gutiérrez Lázaro died mysteriously after séance using a ouija board.

Their father recently died and their mother works long hours at a bar to support the family, leaving Verónica in charge of her younger siblings: twins Lucia and Irene, and Antoñito.

Sister Death tells Verónica that she used to see dark spirits when she was younger, and intentionally blinded herself in an unsuccessful attempt to stop the visions.

The film was inspired when Estefanía Gutiérrez Lázaro (1973–1991) reportedly suffered hallucinations and seizures after performing a séance at a school in Madrid to try to contact her friend's deceased boyfriend who had died six months earlier.

[5] The American magazine Newsweek, referenced by NME, is more cautious and while acknowledging that the case is real, likens the event to the similar pop-culture phenomenon and urban legend The Amityville Horror.

In the same magazine, director Paco Plaza says that he didn't feel bound to portray the real events, clarifying "...the whole story of Veronica and the sisters and Antoñito, this little Marlon Brando with glasses, it’s all a vision.

[2][9] The film's soundtrack also features the songs "Maldito duende", "Entre dos tierras" and "Hechizo" by Héroes Del Silencio (all from their album Senderos de traición (1990)) and an advertising jingle for a brand called "Centella".

Verónica originally released on 25 August 2017 in Spain and was selected for the lineup of the 2017 Toronto International Film Festival's Contemporary World Cinema section.

[6][13] A prequel film titled Sister Death (Hermana Muerte), directed by Paco Plaza and starring Aria Bedmar, was released on Netflix in October 2023.

The website's critical consensus reads, "A scarily effective horror outing, Veronica proves it doesn't take fancy or exotic ingredients to craft skin-crawling genre thrills.

"[15] Jonathan Holland from The Hollywood Reporter gave a negative review of the film and wrote, "The real horror in Veronica is not in the CGI visuals, or in Pablo Rosso's frantic cinematography, or in the aural bombardment of sound effects and music; it’s in the relationship between the children".

"[13] Ed Potton of The Times gave the film a 2 out of 5, and wrote "A considerable buzz online suggested that this Spanish horror might arrest the recent run of iffy Netflix movies.

"[17] Dennis Harvey of Variety wrote that the film's ideas "aren’t ultimately original enough or its scares potent enough to suggest Plaza wouldn’t benefit from trying his directorial hand at someone else’s screenplay.