List of wars: 1900–1944

1900-1919

1900-1919

Start	Finish	Name of Conflict	Belligerents
			Victorious party (if applicable)	Defeated party (if applicable)
1901	1902	Anglo-Aro War	United Kingdom	Aro Confederacy
1902	1925	War of Unification of Saudi Arabia	Sultanate of Nejd Allied Arab clans	Rashidi State Ottoman Empire File:Hejaz flag1.gif Kingdom of Hejaz
1903	1904	British expedition to Tibet
1904	1905	Russo-Japanese War	Empire of Japan	Russian Empire Principality of Montenegro
1904	1909	Black Patch War	United States
1905	1905	1905 Russian Revolution	Russian Empire	Revolutionaries
1906	1909	Pig War	Kingdom of Serbia	Austro-Hungarian Empire
1907	1907	1907 Romanian Peasants' Revolt	Kingdom of Romania
1908	1909	Moroccan War	Morocco
1908	1909	Persian Civil War	Iran
1909	1910	Second Rif War	Spain	Morocco
1909	1911	Nicaraguan Civil War	Nicaragua	Nicaraguan Conservative Rebals United States
1909	1911	Wadai War	France	Ouaddai Empire
1910	1921	Mexican Revolution	Mexico
1911	1912	Second Franco-Moroccan War	France	Morocco
1911	1912	Italo-Turkish War	Kingdom of Italy	Ottoman Empire
1912	1913	First Balkan War	Kingdom of Bulgaria Kingdom of Greece Kingdom of Serbia Kingdom of Montenegro	Ottoman Empire
1912	1916	Contestado War	Brazillian Governists	Rebels
1913	1913	Second Balkan War	Ottoman Empire Kingdom of Greece Kingdom of Serbia Kingdom of Montenegro	Kingdom of Bulgaria
1914	1918 (de facto) 1919 (de jure)	World War I	Triple Entente: Kingdom of Belgium Kingdom of Serbia France Russian Empire (until March 1917) British Empire Kingdom of Italy (from April 1915) United States (from 1917) Kingdom of Montenegro Empire of Japan Portuguese Republic (from March 1916) Kingdom of Romania (August 1916-May 1918) Kingdom of Greece (from June 1917) Albania Brazil (from October 1917) Armenia (from May 1918) Czechoslovakia Finland (from October 1918r) Kingdom of Siam San Marino (from June 1915) China (from August 1917)	Central Powers: Austro-Hungarian Empire German Empire (including German colonial forces) Ottoman Empire Kingdom of Bulgaria
1915	1934	United States occupation of Haiti	United States Haiti	Haiti
1917	1917	1917 Russian Revolution	Bolsheviks	Russian Empire Mensheviks
1917	1922	Russian Civil War	Communist Forces: Russian SFSR Ukrainian SSR Revolutionary Insurrectionary Army of Ukraine	Russian Empire Central Powers (until 1918): Austro-Hungarian Empire German Empire (including German colonial forces) Ottoman Empire Allied Forces (from 1918): Czechoslovakia China Estonia Finland France Greece Kingdom of Italy Empire of Japan Latvia Lithuania Poland Kingdom of Romania Kingdom of Serbia United Kingdom Australia Canada United States
1917	1918	Soviet-Turkish War Part of Russian Civil War	Ottoman Empire	Russian SFSR
1918	1918	Finnish Civil War Part of Russian Civil War	Finnish White Guards German Empire	Finnish Communists Russian SFSR
1918	1918	Georgian-Armenian War	Democratic Republic of Georgia	Democratic Republic of Armenia
1918	1919	German Revolution	German Empire Weimar Republic	Communist Forces: Bavarian Soviet Republic Spartacus League German Communist movements
1918	1919	Greater Poland Uprising	Poland	German Empire
1918	1919	Polish-Ukrainian War	Poland	West Ukrainian People's Republic
1918	1920	Georgian-Ossetian Conflict	Transcaucasian Democratic Federative Republic Democratic Republic of Georgia	Pro-Bolshevik Ossetian rebels Russian SFSR
1918	1920	Armenian-Azerbaijani War	Azerbaijan Democratic Republic Ottoman Empire (1918 only) Russian SFSR (from April 1920) Turkish Revolutionaries (from April 1920)	Democratic Republic of Armenia Republic of Mountainous Armenia Nagorno-Karabakh rebels British Empire (1918 only) Centrocaspian Dictatorship (1918 only)
1918	1920	Estonian War of Independence	Estonia White Russia Latvia United Kingdom Ingria Ober Ost Finnish, Swedish and Danish volunteers	Russian SFSR File:Estonianworkerscommuneflag.gif Estonian Commune Latvian SSR
1918	1920	Latvian War of Independence	Latvia Estonia Poland United Kingdom France	Russian SFSR Latvian SSR
1918	1920	Lithuanian War of Independence	Lithuania Baltic nobility	Russian SFSR Lithuanian-Byelorussian SSR

1919-1929

1919-1929

Start	Finish	Name of Conflict	Belligerents
			Victorious party (if applicable)	Defeated party (if applicable)
1919	1919	Poland–Czechoslovakia War	Czechoslovakia	Poland
1919	1919	Hungarian–Romanian War	Romania	Hungarian Soviet Republic
1919	1923	Turkish War of Independence	Turkish Nationalists	Occupation Forces: British Empire Kingdom of Greece France Kingdom of Italy Democratic Republic of Armenia Ottoman Empire
1919	1919	Third Anglo-Afghan War	Afghanistan	British Empire India
1919	1919	Portuguese Monarchist Civil War	Portuguese Republican Party	Kingdom of Portugal
1919	1920	Italo-Yugoslav War	Kingdom of Italy Free State of Fiume	Kingdom of Serbs, Croats and Slovenes
1919	1921	Polish-Soviet War	Republic of Poland Ukrainian People's Republic	Russian SFSR Ukrainian SSR
1919	1919	First Silesian Uprising	Weimer Republic	Silesian Rebels
1919	1920	Hungarian Revolutionary War	Little Entente: Czechoslovakia Kingdom of Romania France	Hungarian Soviet Republic Slovak Soviet Republic
1919	1921	Franco-Syrian War	France French Syria	Syrian Rebels
1919	1921	Irish War of Independence	Irish Republic	United Kingdom
1919	1922	Greco-Turkish War	Turkish Revolutionaries	Kingdom of Greece
1919	1926	Third Rif War	France Spain	Republic of the Rif
1920	1920	Polish-Lithuanian War	Poland	Lithuania
1920	1920	Second Silesian Uprising	Weimer Republic	German civil government and police of Upper Silesia
1920	1920	Turkish-Armenian War	Turkish Revolutionaries	Democratic Republic of Armenia
1920	1920	Zhili-Anhui War	Zhili clique File:Flag of Manchuria autonomists (1922).png Fengtian clique	Anhui clique
1920	1921	Guangdong–Guangxi War	Old Guangxi clique	Chinese Revolutionary Party
1921	1921	Soviet-Georgian War	Russian SFSR Turkish revolutionaries	Democratic Republic of Georgia
1921	1921	Third Silesian Uprising	Weimer Republic	Silesian Rebels Poland
1921	1922	East Karelian Uprising	Russian SFSR	Finnish and East Karelian rebels
1922	1922	First Zhili-Fengtian War	Zhili clique	File:Flag of Manchuria autonomists (1922).png Fengtian clique
1922	1923	Irish Civil War	Pro-treaty forces	Anti-treaty forces
1924	1924	August Uprising	Soviet Union	Committee for Independence of Georgia
1924	1924	Second Saud–Sharif War	Saudi Arabia British Empire	Hejaz
1924	1924	Second Zhili-Fengtian War	File:Flag of Manchuria autonomists (1922).png Fengtian clique	Zhili clique
1925	1925	The Incident at Petrich	Kingdom of Bulgaria	Kingdom of Greece
1926	1928	Northern Expeditionary War	Republic of China	Beiyang Government
1927	1933	Nicaraguan Civil War	Governmental forces United States	Rebels
1927	1949	Chinese Civil War	Communist Party of China	Republic of China
1928	1929	Afghan Civil War	Barakzai dynasty Tribal supporters British Empire (from 1929)	Tribal rebels Forces of Habibullah Ghazi
1929	1929	Sino-Soviet War of 1929	Soviet Union	Republic of China
1929	1930	Igbo Women's War	Igbo Women of Owerri and Calabar Provinces	Warrent Chiefs British Colonial Forces

1930-1944

1930-1944

Start	Finish	Name of Conflict	Belligerents
			Victorious party (if applicable)	Defeated party (if applicable)
1930	1930	Central Plains War Part of Chinese Civil War	Forces of Chiang Kai-shek	Forces of the coalition of Yan Xishan, Feng Yuxiang and Li Zongren
1931	1932	Japanese invasion of Manchuria	Empire of Japan	Republic of China
1932	1932	Ecuadorian Civil War	Ecuador
1932	1932	Shanghai War of 1932	Republic of China	Empire of Japan
1932	1935	Chaco War	Paraguay	Bolivia
1932	1935	Colombia-Peru War	Peru	Colombia
1934	1934	Austrian Civil War	First Austrian Republic Fatherland's Front	File:SDAPÖ logo.PNG Social Democratic Party of Austria
1934	1934	Saudi-Yemeni War	Saudi Arabia	Yemen
1935	1936	Second Italo-Abyssinian War	Kingdom of Italy	Ethiopian Empire
1936	1939	Spanish Civil War	Nationalist Spain Kingdom of Italy Germany Portugal	Spanish Republic International Brigades Soviet Union Mexico
1937	1945	Second Sino-Japanese War Part of World War II	Republic of China Communist Party of China United States (from 1941) British Empire (from 1941)	Empire of Japan Manchukuo
1938	1938	Changkufeng Incident	Soviet Union	Manchukuo Empire of Japan
1939	1939	Hungarian Invasion of the Carpatho-Ukraine	Kingdom of Hungary	Carpatho-Ukraine
1939	1939	Slovak-Hungarian War	Kingdom of Hungary	Slovak Republic
1939	1939	Italian invasion of Albania	Kingdom of Italy	Albanian Kingdom
1939	1939	Soviet-Japanese Border War (1939)	Soviet Union Mongolia	Empire of Japan Manchukuo
1939	1945	World War II	Allied Powers: From 1939 Poland Australia France New Zealand British Empire Nepal Union of South Africa Canada Czechoslovakia (government-in-exile) From 1940 Norway Belgium Luxembourg Netherlands Free France Kingdom of Greece Kingdom of Yugoslavia From 1941 Soviet Union Panama Costa Rica Dominican Republic El Salvador Haiti Honduras Nicaragua United States Republic of China Guatemala Cuba Philippines From 1942 Indian Empire Mexico Brazil Ethiopia From 1943 Iraq Bolivia Colombia Iran Yugoslavia From 1944 Liberia Peru Kingdom of Italy (formerly a member of the Axis) Kingdom of Romania (formerly a member of the Axis) Bulgaria (formerly a member of the Axis) San Marino (formerly a member of the Axis) Albania 1945 Only Ecuador Paraguay Uruguay Venezuela Turkey Egypt Lebanon Syria Saudi Arabia Argentina Chile	Axis Powers: Germany Kingdom of Italy (Mussolini was murdered, because Italy never wanted to be in the war in the first place) Hungary (from 1940) Empire of Japan (from 1941) Bulgaria (1940-1944) Kingdom of Romania (1941-1944) Non-Axis Co-belligerents: Manchukuo Mengjiang Finland (1941-1944) Kingdom of Iraq (1941 only) Thailand (1942-1945)
1939	1940	Winter War Part of World War II	Finland	Soviet Union
1940	1941	French-Thai War Part of World War II	Vichy France French Indochina	Thailand
1941	1942	Ecuadorian-Peruvian War	Peru	Ecuador
1941	1941	Anglo-Iraqi War Part of World War II	United Kingdom India Palestine	Kingdom of Iraq Germany Kingdom of Italy
1941	1944	Continuation War Part of World War II	Soviet Union United Kingdom	Finland Germany Kingdom of Italy
1944	1949	Greek Civil War	Kingdom of Greece	N.O.F. partisans Democratic Army of Greece
1944	1945	Lapland War	Finland	Germany
1944	1953	Guerilla War in the Baltic states	Soviet Union	The Forest Brothers