The Great Patriotic War (Russian: Вели́кая Оте́чественная война́, Velikaja Otečestvennaja vojna; Ukrainian: Велика Вітчизняна війна, Velyka Vitčyznjana vijna; Belarusian: Вялікая Айчынная вайна, Vjalikaja Ajčynnaja vajna)^[1] is a term used in Russia and other former republics of the Soviet Union (except for the Baltic states and Ukraine^[2]) to describe the conflict fought during the period from 22 June 1941 to 9 May 1945 along the many fronts of the Eastern Front of World War II between the Soviet Union and Nazi Germany and its allies. For some legal purposes its period might be extended to 11 May 1945 to also include the end of the Prague Offensive.^[3]

The end of the Great Patriotic War is commemorated on 9 May.

The term "Patriotic War" refers to the Russian resistance to the French invasion of Russia under Napoleon I, which became known as the Patriotic War of 1812. In Russian, the term отечественная война originally referred to a war on one's own territory (otechestvo means "the fatherland"), as opposed to a campaign abroad (заграничная война),^[4] and later was reinterpreted as a war for the fatherland, i.e. a defensive war for one's homeland. Sometimes the Patriotic War of 1812 was also referred to as the Great Patriotic War (Великая отечественная война); the phrase first appeared no later than 1844^[5] and became popular on the eve of the centenary of the Patriotic War of 1812.^[6]

After 1914, the phrase was applied to World War I.^[7] It was the name of a special war-time appendix to the magazine Theater and Life (Театр и жизнь) in Saint Petersburg, and referred to the Eastern Front of World War I, where Russia fought against the German Empire and the Austro-Hungarian Empire.^[7] The phrases Second Patriotic War (Вторая отечественная война) and Great World Patriotic War (Великая всемирная отечественная война) were also used during World War I in Russia.^[7]

The term Great Patriotic War re-appeared in the Soviet newspaper Pravda on 23 June 1941, just a day after Nazi Germany invaded the Soviet Union. It was found in the title of "The Great Patriotic War of the Soviet People" (Velikaya Otechestvennaya Voyna Sovetskogo Naroda), a long article by Yemelyan Yaroslavsky, a member of Pravda editors' collegium.^[7] The phrase was intended to motivate the population to defend the Soviet fatherland and to expel the invader, and a reference to the Patriotic War of 1812 was seen as a great morale booster.

The term Отечественная война (Patriotic War or Fatherland War) was officially recognized by establishment of the Order of the Patriotic War on 20 May 1942, awarded for heroic deeds.

The term is not generally used outside the former Soviet Union, and the closest term is Eastern Front of World War II (1941-1945). Both terms do not cover the initial phase of World War II in Eastern Europe during which the USSR, then still in a non-aggression pact with Germany, occupied East part of Poland (1939), the Baltic states (1940), and Bessarabia and Northern Bukovina (1940) and fought with Finland (1939-1940).^[3][8]

On 9 April 2015, the Ukrainian parliament replaced the term "Great Patriotic War" (Velyka vitchyzniana viina) in the country's law with "Second World War" (Druha svitova viina),^[9] as part of a set of decommunization laws.