Igor Vsevolodovich Girkin (born 17 December 1970, Moscow, RSFSR, USSR) is a Russian terrorist, military officer, war criminal, blogger, White Movement ideologue, writer, retired Russian Armed Forces officer, former FSB colonel. Participant of the Russian war against Ukraine in Crimea, Donbas and during the 2022 invasion on the side of Russia, as well as a number of other wars: in Transnistria (Moldova), Bosnia, Chechnya. The leader of the Novorossiya terrorist group since 2014, head of the 25 January Committee. Former leader of the pro-Russian terrorist military group 'People's Militia of Donbas'.

After the beginning of Russia's intervention in Crimea, Girkin headed a sabotage unit, organised a gathering of Crimean deputies to call an illegal referendum, and commanded the storming of the photogrammetric centre in Simferopol. In April 2014, he and his unit crossed the border of Ukraine in Donetsk region and led the capture of Sloviansk, thus starting hostilities in Donbas. He became the first "Minister of Defence" of the puppet DPR (16.05.2014-14.08.2014), the commander-in-chief of the "Army of Novorossiya". In August 2014, simultaneously with the beginning of the invasion of Donbas by Russian regular troops, he moved back to Russia.

The SBU and the Prosecutor General's Office of Ukraine opened cases against Girkin for terrorism, violation of Ukraine's sovereignty and territorial integrity, torture and premeditated murder. 

In 2019, the Netherlands put Girkin on the international wanted list as a person involved in the downing of Boeing MH-17. 

On 17 November 2022, he was found guilty of shooting down Boeing MH-17 by the Hague Tribunal, along with Serhiy Dubinsky and Leonid Kharchenko, and sentenced to life in absentia.

On 21 July 2023, Russian security forces detained former militant leader Igor Girkin. On the same day, Moscow's Meshchansky Court imposed a pre-trial restraint on Girkin in the form of detention until 18 September 2023. The investigation has classified the materials in the criminal case as 'top secret'.