List of military legions

• List of Roman legions
  • Theban Legion, a Roman legion whose members, according to a long-lasting tradition, were massacred for their Christian beliefs

• Western Legion and Eastern Legion, Greek rebel forces under Russian command in the Orlov Revolt (1770)
• Lee's Legion (1776–83), an infantry and cavalry unit of the American Continental Army
• Armand's Legion (1778–83), an American dragoon unit
• British Legion (American Revolution) (1778–83), made up of Loyalist American infantry and cavalry
• Lauzun's Legion (1778–82), a composite corps of the French Army comprising cavalry, infantry and artillery elements, mostly recruited from foreign mercenaries
• Jamaica Legion, fighting on the British side in the American War of Independence, involved in the San Juan Expedition (1780).
• Pulaski's Legion (1778–80), one of the few cavalry regiments in the American Continental Army, later merged into Armand's Legion
• Legion of the United States (1792–96), an early United States land force commanded by Anthony Wayne
• French Revolutionary Legion of the Mississippi, a French commissioned force of Americans commanded by George Rogers Clark

• Légion des Allobroges, Swiss, Piedmontese, and Savoyard supporters of the French Revolution
• Batavian Legion, Dutch supporters of the French Revolution in 1793
• Belgian Legion (1792), Liégeois Legion, and Legion of Belgians and Liégeois: Belgian volunteers fighting on the side of the Republicans in the French Revolution
• Irish Legion, a French battalion established in 1803 for a future invasion of Ireland
• King's German Legion, British units of expatriate German personnel that fought against the French during the Napoleonic Wars
• La Legion Noire (The Black Legion), a military unit of the French Revolutionary Army
• Polish Legions (Napoleonic period), Polish units in the service of Napoleonic France
• Russian–German Legion, Germans (as well as Dutch and Belgians) in the service of Tsarist Russia

• Belgian Legion, the name of several units of Belgian volunteers who fought in various 19th century conflicts
• British Legions, foreign volunteer units, established in 1819, who fought against Spain in South America's independence wars
• British German Legion, a group of German soldiers recruited to fight for Britain in the Crimean War, 1855–1856
• Greek Legion (Septinsular Republic), a Septinsular Republic unit active between 1805 and 1807, taking part in the War of the Third Coalition and the Russo-Turkish War (1806–1812)
• Royal Foreign Legion (Légion royal étrangère), infantry corps of mostly German mercenaries forming part of the restored French Bourbon army in 1815, renamed the Hohenlohe Regiment after 1821
• British Legion (1835), officially the Auxiliary Legion, a British military force sent to Spain to support the Liberals and Queen Isabella II against the Carlists in the First Carlist War
• Italian Legion, commanded by Garibaldi in the Uruguayan Civil War
• Academic Legion (Vienna), a revolutionary students' group in Vienna in 1848
• Academic Legion (Lviv), Polish nationalist students at the University of Lviv in 1848
• Greek Volunteer Legion, helping Russia in the Crimean War
• International Legion, a military force formed by Garibaldi in 1860 during the wars of Italian unification
  • The British Legion (1860) British contingent of the above
• Nauvoo Legion, a significant militia in early Mormon history
• List of American Civil War legions, both Confederate and Union
• Guelphic Legion, Hanoverian paramilitary unit supporting George V, deposed king of Hanover, from 1866 to 1870
• Carabinieri legions, the regional units of the Italian gendarmerie, established following the unification of the country.

• Czechoslovak Legions, Czech and Slovak volunteer forces fighting on the Allied Powers side
• French Armenian Legion, part of the French Army; also involved in the Franco-Turkish War of 1918–21
• Georgian Legion (1914–1918), a unit of the German Army recruited from Georgians
• Infantry Regiment of the Academic Legion, formed by volunteer Polish students in 1918, later taken into the regular Polish Army
• Italian Legione Redenta, an Italian military formation that participated in the Siberian Intervention during the Russian Civil War
• Jewish Legion, in the British Army at Gallipoli and Palestine
• Polish Legion in Finland, fighting for the Finns against the Russians
• Polish Legions in World War I, part of the Austro-Hungarian Army
• Puławy Legion, a Polish formation that was part of the Imperial Russian Army
• Legion of Ukrainian Sich Riflemen, a corps of the Austro-Hungarian Army

• 2nd Legions Infantry Division (Poland), elite unite of the Polish Army, mostly composed of veterans of the Polish Legions in World War I
• Condor Legion, a unit of "volunteers" from the German Luftwaffe serving with the Nationalists during the Spanish Civil War
• British Legion Volunteer Police Force, a short-lived police force established in response to the outcome of the Munich Agreement in September 1938
• Aviazione Legionaria, Italian air force in the Spanish Civil War

• Czechoslovak Legion opposing the Germans in Poland, 1939

Note: Except for the above, all World War II legions fought on the German side.

• Free Arabian Legion, Arab volunteers, notably from Iraq, and North Africa fighting on the German side.
• Armenian or Armenische Legion, name given to the 812th Armenian Battalion of the German Army, made up largely of Armenian Red Army prisoners of war
• Azerbaijani Legion (Azerbaijan legion), made up largely of Azerbaijani Red Army prisoners of war
• Blue Legion, Spanish volunteers fighting against the Soviet Union on the Eastern Front
• Crna Legija (Black Legion), the name given to the 1st and 5th Croatian Ustaše Brigades
• Croatian Legion
• Croatian Air Force Legion
• Croatian Anti-Aircraft Legion
• Croatian Naval Legion
• Estonian Legion, a unit in the Waffen SS created in 1942, mainly consisting of Estonian soldiers
• Flemish Legion (Dutch: Vlaams Legioen), recruited among Dutch-speaking volunteers from German-occupied Belgium, notably from Flanders.
• Walloon Legion (French: Légion Wallonie), recruited among French-speaking volunteers from German-occupied Belgium.
• Légion française des combattants (French Legion of Fighters), a pro-Nazi Vichy French unit
• Legion of French Volunteers Against Bolshevism (LVF), pro-Nazi French
• Georgian Legion (1941–1945), a unit of the German army recruited from Georgians
• Indische Legion, also known as the Free India Legion or Tiger Legion, an Indian unit raised in 1941 and attached to the German Army
• Latvian Legion, a formation of the Waffen-SS created in 1943 and consisting primarily of ethnic Latvians
• Legion of St. George, the original name of the British Free Corps
• Ostlegionen (literally "Eastern Legions"), conscripts and volunteers from the occupied eastern territories recruited into the German Army
• La Légion Tricolore, a pro-Nazi French unit which was absorbed into the LVF after six months
• Volga Tatar Legion, one of several units formed by the Wehrmacht out of Soviet prisoners of war according to their ethnicity

• Arab Legion (al-Jaysh al-Arabī) (1920–56), the regular army of Transjordan, predecessor of the present Jordanian Army
• Foreign legion (disambiguation)
  • French Foreign Legion, a unit of the French Army mainly composed of foreigners wishing to fight for France (1831–present)
• Polish Legions (disambiguation), eleven units at different times between the 18th and 20th centuries (some of which are listed separately above)
• Spanish Legion, an elite unit of the Spanish Army (1920–present)

• International Legion of Territorial Defence of Ukraine, a volunteer foreign legion military unit created by the Government of Ukraine to fight in the 2022 Russian invasion of Ukraine

• National Legion, a far right Belgian paramilary and political movement in the 1920s and 1930s, headed by Paul Hoornaert
• Légion Belge, a far right but anti-Nazi World War II Belgian Resistance movement
• White Legion, a Georgian guerrilla group in Abkhazia after the Georgian regular army's defeat in the War in Abkhazia
• Caribbean Legion, active in Central American politics of the 1950s