In representative democracies, gerrymandering (, originally ) is the political manipulation of electoral district boundaries with the intent to create undue advantage for a party, group, or socioeconomic class within the constituency. The manipulation may involve "cracking" (diluting the voting power of the opposing party's supporters across many districts) or "packing" (concentrating the opposing party's voting power in one district to reduce their voting power in other districts). Gerrymandering can also be used to protect incumbents. Wayne Dawkins describes it as politicians picking their voters instead of voters picking their politicians.

The term gerrymandering is named after American politician Elbridge Gerry, Vice President of the United States at the time of his death, who, as governor of Massachusetts in 1812, signed a bill that created a partisan district in the Boston area that was compared to the shape of a mythological salamander. The term has negative connotations, and gerrymandering is almost always considered a corruption of the democratic process. The resulting district is known as a gerrymander (). The word is also a verb for the process.