Flatliner

Flatliner may refer to:


 * A person whose brain or cardiac activity is measured as a flatline
 * The Flatliner Band, a country band from Brighton, IL
 * The Flatliners, a Canadian ska punk rock band
 * Flat-Liner, Australian haunted heavy-rock band
 * 4-Methylthioamphetamine, a psychoactive drug
 * Flatliners, a 1990 science fiction psychological horror film directed by Joel Schumacher
 * Flatliners (2017 film), a 2017 remake of the 1990 film, directed by Niels Arden Oplev
 * "Flatliner" (song), a song by Cole Swindell and Dierks Bentley
 * Another name for the Reverse STO, a professional wrestling move
 * Flatlinerz, a band