Reaction may refer to a response to an action, event, or exposure. Examples:
- First reaction: Sciocc!
- Adverse drug reaction
- Allergic reaction
- Chemical reaction
- Chain reaction (disambiguation)
- Commentary (disambiguation)
- Emotional, reaction
- Hypersensitivity, reaction
- Intolerance (disambiguation), reaction
- Light reaction (disambiguation)
- Nuclear reaction
- Reaction (physics), as defined by Newton's third law
- Reactionary, a political tendency
- Reaction video
- Reflex, reaction
Proper names and titles
- Reaction (album), a 1986 album by American R&B singer Rebbie Jackson
- "Reaction" (song), the title song from the Rebbie Jackson album
- "Reaction", a 2008 single by Dead Letter Circus
- ReAction GUI, a GUI toolkit used on AmigaOS
- Reaction.life, a political news and commentary website edited by Iain Martin
- Reaction Records, a record label
- TNA Reaction, a former documentary show of TNA Wrestling (now known as Impact Wrestling) behind the scenes
- Reaction (The Spectacular Spider-Man), an episode of the American animated television series The Spectacular Spider-Man
- The Reaction, a novel in the Animorphs series
See also
- Action (disambiguation)
- Stimulus (disambiguation)