Equalizer or equaliser (see spelling differences) may refer to:
- Equalization, the process of adjusting the strength of certain frequencies within a signal
- An equalization filter used for audio and similar signals
- An Equalizer (communications) used in telecommunications
- Equalizer (mathematics), the solution set of an equation
- Equaliser (sports), a goal or run that ties the game
- Equalizer (computer program), a program which helps Stephen Hawking to talk.
- The Equalizer, an American action-adventure television series
- GAU-12 Equalizer, a type of Gatling gun
- Equalizer (Datel), a game-hacking cheat cartridge by Datel
- Equal-i-zer, a brand of towing hitch
- "Equalizer" (k-os song), a song by hip hop artist k-os
- A weapon in the video game Team Fortress 2 that deals more damage as the player loses health.
- A term sometimes used to describe a whippletree
- A slang term for a gun