Killers of the Flower Moon: The Osage Murders and the Birth of the FBI is a celebrated work of narrative nonfiction by New Yorker staff writer David Grann, published in trade paperback as a movie tie-in edition by Random House/Doubleday in October 2023.

The book investigates one of the most disturbing crimes in American history: a systematic campaign of murder targeting wealthy members of the Osage Nation in Osage County, Oklahoma, during the early 1920s. After vast oil reserves were discovered beneath their land, the Osage people became among the richest per capita in the world — and then began dying under mysterious circumstances. Grann uncovers a conspiracy that reached far deeper than official records suggested, with potentially hundreds of victims. The investigation ultimately helped launch the modern FBI and led to the conviction of cattleman William King Hale as the plot's mastermind.

Named one of Time magazine's top ten nonfiction books of 2017, the book received widespread critical acclaim. The New York Times called it "close to impeccable," and Rolling Stone praised it as a "masterful" chronicle of murder, betrayal, and America's struggle with its own history. The movie tie-in edition coincides with the major Martin Scorsese film adaptation starring Leonardo DiCaprio, Robert De Niro, and Lily Gladstone, released by Paramount Pictures in October 2023.