Ari Aster (born July 15, 1986) is an American filmmaker.

After garnering initial recognition for the short film The Strange Thing About the Johnsons (2011), he became best known for writing and directing the feature films Hereditary (2018) and Midsommar (2019), both released by A24, making a name as a filmmaker of elevated horror. After pivoting away from the genre with Beau Is Afraid (2023), his next film, Eddington, premiered in competition at the 2025 Cannes Film Festival. His films are notable for their unsettling combination of horror, dark comedy, and graphic violence. He co-founded the production company Square Peg with Danish producer Lars Knudsen in 2019.