Reactor may refer to:
Science Bioreactor, a device which controls a biologically active environment. Chemical reactor, a device for containing and controlling a chemical reaction Fusion reactor, a device for containing and controlling a fusion power reaction An inductor (possessing reactance) in an electrical power grid A current limiting reactor is used to limit starting current of motors and to protect variable frequency drives Nuclear reactor, a device for containing and controlling a nuclear reaction Breeder reactor Reactor (software), a physics simulation engine The reactor design pattern, a design pattern used in concurrent programming
Entertainment Reactor (magazine), an online science fiction and fantasy magazine, formerly known as Tor.com Reactor (album), a 1981 album by Neil Young and Crazy Horse Reactor (arcade game), an arcade game created by Gottlieb Reactor (Supergame), a 1983 adventure for the role-playing game Supergame The Reactor (show rod), a show car built by Gene Winfield Reactor, an alternate title for Deadlock, a 2021 American action thriller film starring Bruce Willis Reactor, an alternative title for the 1978 Italian film War of the Robots directed by Alfonso Brescia Reactor, Inc., a defunct interactive entertainment company founded by Mike Saenz Reactor, a comedy series hosted by David Huntsberger on Syfy