Never Flinch is a 439-page crime thriller novel by Stephen King, published on May 27, 2025 by Scribner (a Simon & Schuster imprint). It is the fourth novel in King's acclaimed Holly Gibney series, following Mr. Mercedes (2014), Finders Keepers (2015), End of Watch (2016), The Outsider (2018), and Holly (2023).

The story opens when the Buckeye City Police Department receives a chilling letter from an unknown assailant threatening to kill thirteen innocents and one guilty person as an act of retribution for the wrongful death of an innocent man in prison. Simultaneously, private investigator Holly Gibney is hired to serve as bodyguard for Kate McKay, a prominent feminist activist embarking on a multi-state lecture tour who is being stalked and threatened by a dangerous antagonist. Holly must navigate both cases as the body count threatens to rise and her own life comes under threat.

Publishers Weekly praised the novel, writing that "Holly shines as a quirky but lovable beacon of hope amid the plot's grisly violence, and King never lets his Rube Goldberg-esque plot overshadow his characters' humanity." The New York Times noted the novel's cinematic style and King's sharp social critique. The audiobook edition is read by Jessie Mueller.