Heart surgery scenes in the film are real. They were filmed during an operation on a real patient who was undergoing quadruple bypass surgery which Colin Farrell attended.
The film's title comes from the ending of the tragedy Iphigenia in Aulis by Euripides.
Colin Farrell admittedly felt nauseous after reading the script for the film.
Alicia Silverstone and Nicole Kidman were cast because they were both fans of Yorgos Lanthimos, and begged him to cast them. Silverstone later said, "I would just die to work with him again."
Nicole Kidman and Colin Farrell began working together on Les proies (2017), only a few weeks after they wrapped filming on this film. Both films would go on to be in competition for the Palme d'Or at the 2017 Cannes Film Festival, and both would win awards in the official competition ("The Beguiled" won the Directing award for Sofia Coppola while "The Killing of a Sacred Deer" shared the Screenplay award with Lynne Ramsay's Tu n'as jamais été vraiment là (2017)).