Lullaby (; published as The Perfect Nanny in the United States) is a 2016 novel by French author Leïla Slimani.
The book deals with the murder of two children by their nanny. It was inspired by the real-life 2012 murder of children by their nanny in New York.
Lullaby is Slimani's second novel and the first to be translated into English. By January 2018 it had been translated into 18 languages, with intentions for a further 17. Originally titled Chanson douce, it was translated as Lullaby for the UK and The Perfect Nanny in the US.
It sold 600,000 copies in France in its first year of publication.
Lullaby was described by Aida Edemariam (writing in The Guardian) as "stylishly written [...] brilliantly executed". It was compared to Gone Girl by both Celia Walden of The Telegraph and Lucy Scholes of The Independent, with the latter describing it as "a psychological thriller that will have readers on the edge of their seats".
The novel won the 2016 Prix Goncourt, a top French literary award.
In 2019, a film adaptation, of the same name in certain countries and entitled Perfect Nanny in some others, was made by director Lucie Borleteau, starring Karin Viard, Leïla Bekhti and Antoine Reinartz.
In January 2023, it was reported that a planned television limited series adaptation entitled The Perfect Nanny was in development at HBO with Legendary Television co-producing. Nicole Kidman and Maya Erskine are set to star.