Russian separatist forces in Ukraine, primarily the People's Militias of the Donetsk People's Republic (DPR) and the Luhansk People's Republic (LPR), were pro-Russian paramilitaries in the Donbas region of eastern Ukraine. They were under the overall control of the Russian Federation, and were also referred to as Russian proxy forces. They were active during the war in Donbas (2014–2022), the first stage of the Russo-Ukrainian War. They then supported the Russian Armed Forces against the Ukrainian Armed Forces during the 2022 Russian invasion. In September 2022, Russia annexed the DPR and LPR, and began integrating the paramilitaries into its armed forces. They are designated as terrorist groups by the government of Ukraine.

The war in Donbas, or Donbas war, was a phase of the Russo-Ukrainian War in the Donbas region of Ukraine. The war began 12 April 2014, when a fifty-man commando unit headed by Russian citizen Igor Girkin seized Sloviansk in Donetsk oblast. The Ukrainian military launched an operation against them. It continued until it was subsumed by the Russian invasion of Ukraine in February 2022.