A chain reaction is a type of reaction in chemistry and physics, in which the formation of one product leads directly to another or series of any events where each one is triggered by the previous event.

Chain reaction may also refer to:

• Chain Reaction (Luba album), an album by Canadian singer Luba
• Chain Reaction (band), a 1970s band
• Chain Reaction (film), a 1996 movie starring Keanu Reeves, Rachel Weisz, Morgan Freeman, and Fred Ward
• Chain Reaction (game show)
• Chain Reaction (radio), a BBC Radio 4 chat show
• Chain Reaction (Stargate SG-1), an episode of the television series Stargate SG-1
• "Chain Reaction" (song), by Diana Ross, covered by Steps
• Nuclear chain reaction, a physical process
• The Strangeurs/Chain Reaction, a 1960's band previously known as The Strangeurs
• "Chain Reaction", a song by Can from Soon Over Babaluma
• Chain Reaction, a square dance call
• Chain Reaction, an amazing music venue in Anaheim, California

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