Activator

Activator may refer to:
 * Activator (genetics), a DNA-binding protein that regulates one or more genes by increasing the rate of transcription
 * Activator (phosphor), a type of dopant used in phosphors and scintillators
 * Enzyme activator, a type of effector that increases the rate of enzyme mediated reactions
 * Sega Activator, a motion-sensing controller for the Sega Mega Drive/Genesis
 * Activator technique, a method of spinal adjustment
 * Activator appliance, an orthodontic functional appliance