Anaïs Aude Marie Michèle Demoustier (born 29 September 1987) is a French actress. She was twice nominated for the César Award in the Most Promising Actress category: in 2009 for the film Les Grandes Personnes and in 2011 for the film Living on One's Own. In 2020 she won the César for Best Actress for her role in the film Alice and the Mayor.

In April 2023, Demoustier was announced as president of the Caméra d'Or jury at the 2023 Cannes Film Festival.

During the filming of Marguerite et Julien, Demoustier began dating her co-star Jérémie Elkaïm. In December 2015, it was announced that the couple were expecting their first child. In March 2016, Demoustier gave birth to a daughter.

Her brother Stéphane Demoustier is a director and screenwriter.