Sergey Kirov, Russian politician (d. 1934)
Sergei Mironovich Kirov (born Sergei Mironovich Kostrikov; 27 March 1886 – 1 December 1934) was a Soviet politician and Bolshevik revolutionary whose assassination led to the first Great Purge.

Kirov was an early revolutionary in the Russian Empire and member of the Bolshevik faction of the Russian Social Democratic Labour Party. Kirov became an Old Bolshevik and personal friend to Joseph Stalin, rising through the Communist Party of the Soviet Union ranks to become head of the party in Leningrad and a member of the Politburo.

On 1 December 1934, Kirov was shot and killed by Leonid Nikolaev at his offices in the Smolny Institute for unknown reasons; Nikolaev and several suspected accomplices were convicted in a show trial and executed less than 30 days later. Kirov's death was later used as a pretext for Stalin's escalation of political repression in the Soviet Union and the events of the Great Purge, with complicity as a common charge for the condemned in the Moscow Trials. Kirov's assassination remains controversial and unsolved, with varying theories regarding the circumstances of his death.