Declarations of war during World War II
Animated map of the European Theater of war during WWII
This is a timeline of formal declarations of War during World War II.
A declaration of war is a formal act by which one nation goes to war against another. The declaration is usually an act of delivering a performative speech (not to be confused with a mere speech) or the presentation of a signed document by an authorized party of a national government in order to create a state of war between two or more sovereign states. The official international protocol for declaring war was defined in The Hague Peace Conference of 1907 (or Hague II).[1] For the diplomatic maneuvering behind these events, which led to hostilities between nations during World War II, see the article entitled Diplomatic history of World War II.
List of war declarations
Below is a table showing the outbreak of wars between nations which occurred during World War II. Indicated are the dates (during the immediate build-up to, or during the course of, World War II), from which a de facto state of war existed between nations. The table shows both the "Initiator Nation(s)" and the nation at which the aggression was aimed, or "Targeted Nation(s)". Events listed include those in which there were simple diplomatic breaking of relations that did not involve any physical attack, as well as those involving overt declarations or acts of aggression. In rare cases, war between two nations occurred twice, with an intermittent period of peace. The list here does not include peace treaties or periods of any armistice.
Table Legend: Concerning Declaration of War: A = Attack without prior, formal declaration of war; U = State of war arrived at through use of ultimatum;
W = Formal declaration of war made.
| Date | Initiator nation(s) | Targeted nation(s) | Declaration of war: Type | Notes/comments | Document/event |
|---|---|---|---|---|---|
| 1939-09-01 |  Nazi Germany |  Poland | U[2][3] | German attack began at 4:44 am[2][4] | Invasion |
| 1939-09-01 |  Slovak Republic | Poland | A | Invasion | |
| 1939-09-03 |  United Kingdom  France | Nazi Germany | U[2][3] | At 11 a.m., British PM, Neville Chamberlain publicly delivered his Ultimatum Speech.[3][5][6] | Declaration |
| 1939-09-03 |  Australia  New Zealand | Nazi Germany | W[2][3] | Australia New Zealand | |
| 1939-09-04 |  Nepal | Nazi Germany | W | Declaration | |
| 1939-09-06 |  South Africa | Nazi Germany | W[2][3] | Declaration | |
| 1939-09-10 |  Bahrain  Canada  Oman | Nazi Germany | W[2][3] | Declaration Declaration Declaration | |
| 1939-09-17 |  Soviet Union | Poland | A[2][3] | Invasion | |
| 1939-11-30 | Soviet Union |  Finland | A[2][3] | First war between these nations. | Invasion |
| 1940-04-09 | Nazi Germany |  Denmark  Norway | A[2] | Invasion of Denmark Invasion of Norway | |
| 1940-04-12 | United Kingdom | Faroe Islands | A[3] | Invasion | |
| 1940-05-10 | Nazi Germany |  Belgium  Netherlands | A/W[2][3] | Date of the German offensive in the West, W from Belgium and the Netherlands.[7] | Belgium Netherlands |
| 1940-05-10 | Nazi Germany |  Luxembourg | A[3] | Luxembourg | |
| 1940-05-10 | United Kingdom |  Iceland | A | Invasion | |
| 1940-06-10 |  Italy |  France United Kingdom | W[2][3] | France and the UK | |
| 1940-06-10 | Canada | Italy | W[2] | Declaration | |
| 1940-06-11 | South Africa Australia New Zealand | Italy | W[2] | South Africa Australia New Zealand | |
| 1940-06-11 | France | Italy | W[2] | Declaration | |
| 1940-06-16 | Soviet Union |  Lithuania | A | Occupation | |
| 1940-06-17 | Soviet Union |  Estonia Latvia | A | Occupation | |
| 1940-06-25 | United Kingdom | Vichy France | A | Vichy France cuts off diplomatic relations with the United Kingdom on 8 July 1940. | Attack |
| 1940-09-09 | Italy |  Egypt | A | Egypt maintained neutrality until 1945. | Invasion |
| 1940-09-22 |  Japan | Vichy France | A | Invasion | |
| 1940-09-23 |  Free France Australia | Vichy France | A | Invasion | |
| 1940-10-?? |  Thailand | Vichy France | A | Franco-Thai War | |
| 1940-10-28 | Italy |  Greece | U[3] | Italy invades Greece | Invasion |
| 1941-02-05 | Free France | Italy | A | Invasion | |
| 1941-04-06 | Nazi Germany | Greece | W[2][3] | Invasion | |
| 1941-04-06 | Nazi Germany  Bulgaria |  Yugoslavia | A[2][3] | Invasion | |
| 1941-04-06 | Italy  Hungary | Yugoslavia | A[3] | Invasion | |
| 1941-04-14 | Nazi Germany | Egypt | A | Egypt maintained neutrality until 1945. | Invasion |
| 1941-05-02 | United Kingdom |  Iraq | A | Invasion | |
| 1941-06-08 | Free France | Nazi Germany | A | Invasion | |
| 1941-06-22 | Nazi Germany Italy  Romania | Soviet Union | A[2][3] | A timed-declaration of war was given by Germany at the time of the attack[8] | Invasion |
| 1941-06-22 |  Tuva | Nazi Germany | W | Tuva was a client state of the Soviet Union. Part of the USSR from 1944. | |
| 1941-06-25 | Finland | Soviet Union | W | Finland recognized a state of war with the Soviet Union; second war between these nations. | Continuation War |
| 1941-06-27 | Hungary | Soviet Union | W[3] | Invasion | |
| 1941-08-25 | Soviet Union United Kingdom Australia |  Iran | A | Invasion | |
| 1941-12-06 | United Kingdom | Finland | U[3] | Declaration | |
| 1941-12-07 | United Kingdom | Romania Hungary | U[3] | Declaration | |
| 1941-12-07 | Japan |  United States United Kingdom | A[2] | W (Japanese point of view); A (British Empire and United States) | Declaration Attack on Pearl Harbor Invasion of Malaya Attack on Singapore Invasion of Hong Kong |
| 1941-12-07 | Canada Australia New Zealand | Japan Finland Romania Hungary | W[3] | Canada Australia New Zealand | |
| 1941-12-07 | United Kingdom | Romania Finland Hungary | W[3] | Declaration | |
| 1941-12-07 |  Panama | Japan | W[3] | Declaration | |
| 1941-12-08 | United States United Kingdom Australia  Costa Rica  Dominican Republic  El Salvador  Guatemala  Haiti  Honduras Netherlands New Zealand  Nicaragua  Philippines | Japan | W[3] | United States declaration British declaration | |
| 1941-12-08 | South Africa | Japan | W[3] | South African declaration | |
| 1941-12-08 |  China | Italy Japan | W[3] | China and Japan had been at war since 1937 | Second Sino-Japanese war Declaration |
| 1941-12-08 |  Mongolia | Nazi Germany | W[citation needed] | Mongolian declaration | |
| 1941-12-09 | Australia New Zealand | Japan | W[3] | Australian declaration New Zealand's declaration | |
| 1941-12-11 | Nazi Germany Italy | United States | W[2][3] | German declaration Italian declaration | |
| 1941-12-11 | United States | Nazi Germany Italy | W[2] | Germany Italy | |
| 1941-12-11 | Poland (in-exile) | Japan | W[2] | Japan rejected declaration of War. Prime Minister Hideki Tōjō's answer was following: "We don't accept the Polish declaration of war. The Poles, fighting for their freedom, declared war under the British pressure". | |
| 1941-12-12 | Romania Bulgaria | United States United Kingdom | W[3] | Romanian declaration Bulgarian declaration | |
| 1941-12-12 | Australia Netherlands |  Portugal | A | Portugal maintained neutrality throughout World War II. | Invasion |
| 1941-12-13 | United Kingdom New Zealand South Africa | Bulgaria | W[3] | British declaration New Zealand's declaration South African declaration | |
| 1941-12-13 | Hungary | United States | W[3] | Declaration | |
| 1941-12-14 |  Independent State of Croatia | United States United Kingdom | W[3] | Declaration | |
| 1941-12-16 |  Czechoslovakia (In-exile) | Nazi Germany Italy Finland Romania Hungary  Japan Bulgaria Independent State of Croatia[9] | W | Declaration | |
| 1941-12-17 |  Albania | United States | W | Declaration | |
| 1941-12-19 |  Nicaragua | Bulgaria Hungary Romania | W | Declaration | |
| 1941-12-20 | Belgium | Japan | W | Declaration | |
| 1942-01-01 | United Nations | Axis Powers | W | Declared during Arcadia Conference | Declaration |
| 1942-01-06 | Australia | Bulgaria | W | Declaration | |
| 1942-01-16 | Iraq | Nazi Germany Italy Japan | W | Declaration | |
| 1942-01-25 | Thailand | United Kingdom United States | A | Declaration | |
| 1942-01-25 | United Kingdom New Zealand South Africa | Thailand | W | British declaration New Zealand's declaration South African declaration | |
| 1942-02-12 |  Peru | Nazi Germany Japan | W | Declaration | |
| 1942-02-19 | Japan | Portugal | A | Portugal maintained neutrality throughout World War II. | Invasion |
| 1942-05-05 | South Africa Netherlands (in-exile) Poland | Vichy France | A | Invasion | |
| 1942-05-05 | United Kingdom  Northern Rhodesia  Southern Rhodesia South Africa  Tanganyika  Belgian Congo | Vichy France Japan | A | Invasion | |
| 1942-05-22 |  Mexico | Nazi Germany Italy Japan | W[3] | Declaration | |
| 1942-08-22 |  Brazil | Nazi Germany Italy | W | Declaration | |
| 1942-11-08 | United States Canada | Vichy France | A | Invasion | |
| 1942-11-10 | Nazi Germany Italy | Vichy France | A | Invasion | |
| 1942-12-14 |  Ethiopia | Nazi Germany Italy Japan | W | On 3 October 1935, Italy invaded Ethiopia without a formal declaration of war. In response to the Italian invasion, Ethiopia declared war on Italy. Most of Ethiopia was occupied by Italy in 1936, however parts of Ethiopia remained under the control of the Ethiopian Patriots Movement, which begun its guerrilla war against the occupying Italian forces the day Addis Ababa fell in May 1936. In May 1941, Addis Ababa was liberated by the Gideon Force, restoring sovereignty to Ethiopia. | Second Italo-Ethiopian War Declaration |
| 1943-09-01 |  China Regime of Wang Jingwei | Allied Powers | W | Declaration | |
| 1943-04-02 |  Bolivia | Axis powers | W | Declaration | |
| 1943-09-09 | Iran | Nazi Germany | W | Declaration | |
| 1943-10-13 | Italy | Nazi Germany | W[2] | Italy had changed sides after the fall of Mussolini. The Declaration of War was given by Pietro Badoglio to the German ambassador in Madrid.[2] | Declaration |
| 1943-11-26 |  Colombia | Nazi Germany | W | Declaration | |
| 1944-01-17 | Free France |  Italian Social Republic | A | Invasion | |
| 1944-01-27 |  Liberia | Nazi Germany Japan | W | Declaration | |
| 1944-06-06 | France | Nazi Germany | A | Invasion | |
| 1944-07-25 | France | Japan | A | Invasion | |
| 1944-08-25 | Romania | Nazi Germany Hungary | W | Romania switched sides | Declaration |
| 1944-09-05 | Soviet Union | Bulgaria | W | Declaration | |
| 1944-09-08 | Bulgaria | Nazi Germany | W | Bulgaria switched sides | Declaration |
| 1944-09-15 | Nazi Germany | Finland | A | Lapland War | |
| 1944-09-23 |  Second Philippine Republic | United States United Kingdom | W[10] | Philippine declaration | |
| 1944-12-31 | Hungary | Nazi Germany | W[11] | Hungary switched sides | Declaration |
| 1945-02-02 |  Ecuador | Nazi Germany Japan | W | Ecuadorian declaration | |
| 1945-02-07 |  Argentina  Paraguay | Nazi Germany Japan | W | Argentinean declaration Paraguayan declaration | |
| 1945-02-15 |  Venezuela  Uruguay | Nazi Germany Japan | W | Venezuelan declaration Uruguayan declaration | |
| 1945-02-21 |  San Marino | Nazi Germany | W | Declaration | |
| 1945-02-23 |  Turkey | Nazi Germany Japan | W | Declaration | |
| 1945-02-24 | Egypt | Nazi Germany Japan | W | Declaration | |
| 1945-02-26 |  Syria  Lebanon | Nazi Germany Japan | W | Declaration | |
| 1945-04-01 |  Saudi Arabia | Japan | W | Declaration | |
| 1945-04-03 | Finland | Nazi Germany | W | Finland switched sides | Lapland War |
| 1945-04-11 |  Chile | Japan | W | Declaration | |
| 1945-07-06 | Brazil | Japan | W | Declaration | |
| 1945-07-09 | Norway | Japan | W | Declaration[12] | |
| 1945-07-14 | Italy | Japan | W | Declaration | |
| 1945-08-08 | Soviet Union | Japan | W[2] | Last outbreak of war during the entire Second World War. | Declaration |
| 1945-08-10 | Mongolia | Japan | W[13] | W (de jure) A (de facto 1945-08-09) War declared 24 hours after crossing the border with Soviet troops | Soviet Invasion of Manchuria Mongolia in World War II |
German ambassador, Hans-Adolf von Moltke, Polish leader Józef Piłsudski, German propaganda minister Joseph Goebbels and Józef Beck, Polish Foreign minister meeting in Warsaw on June 15, 1934, five months after signing the Polish-German Non-Aggression Pact.
British Prime Minister Neville Chamberlain, landing at Heston aerodrome on 30 September 1938 after his meeting with Hitler at Munich. In his hand he holds the peace agreement between Britain and Germany.
Common parade of German Wehrmacht and Soviet Red Army on September 23, 1939 in Brest, Eastern Poland at the end of the Poland Campaign. In the center is Major General Heinz Guderian; and on the right is Brigadier General Semyon Krivoshein.
Counsellor of state J.K. Paasikivi and his team arriving from Moscow for the first round of negotiations on 16 October 1939. From left, minister Aarno Yrjö-Koskinen, J.K. Paasikivi, chief of staff Johan Nykopp and colonel Aladár Paasonen.
German paratroopers taking the Greek island of Crete, May 1941.
Photograph from a Japanese plane of Battleship Row at the beginning of the surprise Attack on Pearl Harbor. The explosion in the center is a torpedo strike on the USS Oklahoma. Two attacking Japanese planes can be seen: one over the USS Neosho and one over the Naval Yard.
Literature about the war
Harman, Nicholas (1990). Dunkirk: the Necessary Myth. Jove. ISBN 978-0340517857..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"""""""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
German White Book. All World Wars.
Hitler, Adolph (2012). The Great Tragedy: Germany's Declaration of War against the United States of America. ISBN 978-1300127703.
Torrie, Julia S. (2010). "For Their Own Good": Civilian Evacuations in Germany and France, 1939–1945. Berghahn Books. ISBN 978-1845457259.
References
^ On the Opening of Hostilities; 1907; Yale Law School Library; retrieved March 2014.
^ abcdefghijklmnopqrstuvwx "2194 Days of War"; (1977); Salmaggi, C. & Pallasvini, A.;
ISBN 91-582-0426-1; per tables included. [Italian; American]
^ abcdefghijklmnopqrstuvwxyzaaabacadaeafag Timeline Data Archived May 5, 2016, at the Wayback Machine; World at War online; retrieved February 2014.
^ On This Day
^ Note: Included in the speech: "...This morning, the British Ambassador in Berlin handed the German Government a final note, stating that unless we heard from them by 11 O'clock that they were prepared at once to withdraw their troops from Poland a state of war would exist between us. I have to tell you now that no such undertaking has been received and that consequently this country is at war with Germany..."
^ 1939: Britain and France declare war on Germany, BBC
^ Swedish Encyklopedia; "Bonniers Lexikon" (Vol. 1); (c.1960s); table in article by Andra Världskriget: The Second World War; Pp. 461-462.
^ "The Rise and Fall of the Third Reich"; Shirer, William L
^ all countries at war with the United States, United Kingdom, or the Soviet Union
^ [1]
^ Hungary declares war on Germany
^ https://trove.nla.gov.au/newspaper/article/2634950
^ Christopher P. Atwood (1999), "Sino-Soviet Diplomacy and the Second Partition of Mongolia, 1945–1946", Mongolia in the Twentieth Century: Landlocked Cosmopolitan, Bruce A. Elleman and Stephen Kotkin, eds. (Armonk, NY: M. E. Sharpe), 147.
