Declarations of war during World War II

Table columns:
Date
Initiator Nation(s)
Targeted Nation(s)
Declaration of War: Type
Notes/Comments
Document/Event

Table rows:
cells: 1939-09-01
Nazi Germany
Poland
A[3][4]
German attack began at 4:44 am[3][5]
Invasion
cells: 1939-09-01
Slovak Republic
Poland
A
Invasion
cells: 1939-09-03
United Kingdom  France
Nazi Germany
U[3][4]
At 11 a.m., British PM, Neville Chamberlain publicly delivered his Ultimatum Speech.[4][6][7]
Document Declaration
cells: 1939-09-03
Australia  New Zealand
Nazi Germany
W[3][4]
Australia New Zealand
cells: 1939-09-04
Nepal
Nazi Germany
W
Declaration
cells: 1939-09-06
South Africa
Nazi Germany
W[3][4]
Declaration
cells: 1939-09-10
Bahrain  Canada  Oman
Nazi Germany
W[3][4]
Declaration Declaration Declaration
cells: 1939-09-17
Soviet Union
Poland
A[3][4]
Invasion
cells: 1939-11-30
Soviet Union
Finland
A[3][4]
First war between these nations.
Invasion
cells: 1940-04-09
Nazi Germany
Denmark  Norway
A[3]
Invasion of Denmark Invasion of Norway
cells: 1940-04-12
United Kingdom
Faroe Islands
A[4]
Invasion
cells: 1940-05-10
Nazi Germany
Belgium  Netherlands
A/W[3][4]
Date of the German offensive in the West, W from Belgium and the Netherlands.[8]
Belgium Netherlands
cells: 1940-05-10
Nazi Germany
Luxembourg
A[4]
Luxembourg
cells: 1940-05-10
United Kingdom
Iceland
A
Invasion
cells: 1940-06-10
Italy
France  United Kingdom
W[3][4]
France and the UK
cells: 1940-06-10
Canada
Italy
W[3]
Declaration
cells: 1940-06-11
South Africa  Australia  New Zealand
Italy
W[3]
South Africa Australia New Zealand
cells: 1940-06-11
France
Italy
W[3]
Declaration
cells: 1940-06-16
Soviet Union
Lithuania
A
Occupation
cells: 1940-06-17
Soviet Union
Estonia  Latvia
A
Occupation
cells: 1940-06-25
United Kingdom
Vichy France
A
Vichy France cuts off diplomatic relations with the United Kingdom on 8 July 1940.
Attack
cells: 1940-09-09
Italy
Egypt
A
Egypt maintained neutrality until 1945.
Invasion
cells: 1940-09-22
Japan
Vichy France
A
Invasion
cells: 1940-09-23
Free France  Australia
Vichy France
A
Invasion
cells: 1940-10-??
Thailand
Vichy France
A
Franco-Thai War
cells: 1940-10-28
Italy
Greece
U[4]
Italy invades Greece
Invasion
cells: 1941-02-05
Free France
Italy
A
Invasion
cells: 1941-04-06
Nazi Germany
Greece
W[3][4]
Invasion
cells: 1941-04-06
Nazi Germany  Bulgaria
Yugoslavia
A[3][4]
Invasion
cells: 1941-04-06
Italy  Hungary
Yugoslavia
A[4]
Invasion
cells: 1941-04-14
Nazi Germany
Egypt
A
Egypt maintained neutrality until 1945.
Invasion
cells: 1941-05-02
United Kingdom
Iraq
A
Invasion
cells: 1941-06-08
Free France
Nazi Germany
A
Invasion
cells: 1941-06-22
Nazi Germany  Italy  Romania
Soviet Union
A[3][4]
A timed-declaration of war was given by Germany at the time of the attack[9]
Invasion
cells: 1941-06-22
Tuva
Nazi Germany
W
Tuva was a client state of the Soviet Union. Part of the USSR from 1944.
cells: 1941-06-25
Finland
Soviet Union
W
Finland recognized a state of war with the Soviet Union; second war between these nations.
Continuation War
cells: 1941-06-27
Hungary
Soviet Union
W[4]
Invasion
cells: 1941-08-25
Soviet Union  United Kingdom  Australia
Iran
A
Invasion
cells: 1941-12-06
United Kingdom
Finland
U[4]
Declaration
cells: 1941-12-07
United Kingdom
Romania  Hungary
U[4]
Declaration
cells: 1941-12-07
Japan
United States  United Kingdom
A[3]
W (Japanese point of view); A The "Western" (Attack on Pearl Harbor);
Declaration Attack on Pearl Harbor Invasion of Malaya Attack on Singapore Invasion of Hong Kong
cells: 1941-12-07
Canada  Australia  New Zealand
Japan  Finland  Romania  Hungary
W[4]
Canada Australia New Zealand
cells: 1941-12-07
United Kingdom
Romania  Finland  Hungary
W[4]
Declaration
cells: 1941-12-07
Panama
Japan
W[4]
Declaration
cells: 1941-12-08
United States  United Kingdom  Australia  Philippines  Costa Rica  Dominican Republic  El Salvador  Guatemala  Haiti  Honduras  Netherlands  New Zealand  Nicaragua
Japan
W[4]
British declaration Australian declaration Cost Rican declaration Dominican Republic's declaration Salvadorian declaration Haitian declaration Honduran declaration Dutch declaration New Zealand's declaration Nicaraguan declaration Philippine declaration
cells: 1941-12-08
South Africa
Japan
W[4]
South African declaration
cells: 1941-12-08
China
Italy  Japan
W[4]
China and Japan had been at war since 1937
Second Sino-Japanese war Declaration
cells: 1941-12-08
Mongolia
Nazi Germany
W[citation needed]
Mongolian declaration
cells: 1941-12-09
Australia  New Zealand
Japan
W[4]
Australian declaration New Zealand's declaration
cells: 1941-12-11
Nazi Germany  Italy
United States
W[3][4]
German declaration Italian declaration
cells: 1941-12-11
United States
Nazi Germany  Italy
W[3]
Germany Italy
cells: 1941-12-11
Poland (in-exile)
Japan
W[3]
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".
cells: 1941-12-12
Romania  Bulgaria
United States  United Kingdom
W[4]
Romanian declaration Bulgarian declaration
cells: 1941-12-12
Australia  Netherlands
Portugal
A
Portugal maintained neutrality throughout World War II.
Invasion
cells: 1941-12-13
United Kingdom  New Zealand  South Africa
Bulgaria
W[4]
British declaration New Zealand's declaration South African declaration
cells: 1941-12-13
Hungary
United States
W[4]
Declaration
cells: 1941-12-14
Independent State of Croatia
United States  United Kingdom
W[4]
Declaration
cells: 1941-12-16
Czechoslovakia (In-exile)
Nazi Germany  Italy  Finland  Romania  Hungary  Japan  Bulgaria  Independent State of Croatia[10]
W
Declaration
cells: 1941-12-17
Albania
United States
W
Declaration
cells: 1941-12-19
Nicaragua
Bulgaria  Hungary  Romania
W
Declaration
cells: 1941-12-20
Belgium
Japan
W
Declaration
cells: 1942-01-01
United Nations
Axis Powers
W
Declared during Arcadia Conference
Declaration
cells: 1942-01-06
Australia
Bulgaria
W
Declaration
cells: 1942-01-16
Iraq
Nazi Germany  Italy  Japan
W
Declaration
cells: 1942-01-25
United Kingdom  New Zealand  South Africa
Thailand
W
British declaration New Zealand's declaration South African declaration
cells: 1942-01-19
Japan
Portugal
A
Portugal maintained neutrality throughout World War II.
Invasion
cells: 1942-05-05
South Africa  Netherlands (in-exile)  Poland
Vichy France
A
Invasion
cells: 1942-05-05
United Kingdom  Northern Rhodesia  Southern Rhodesia  South Africa  Tanganyika  Belgian Congo
Vichy France  Japan
A
Invasion
cells: 1942-05-22
Mexico
Nazi Germany  Italy  Japan
W[4]
Declaration
cells: 1942-08-22
Brazil
Nazi Germany  Italy
W
Declaration
cells: 1942-11-08
United States  Canada
Vichy France
A
Invasion
cells: 1942-11-10
Nazi Germany  Italy
Vichy France
A
Invasion
cells: 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
cells: 1943-09-01
China Regime of Wang Jingwei
Allied Powers
W
Declaration
cells: 1943-04-02
Bolivia
Axis Powers
W
Declaration
cells: 1943-09-09
Iran
Nazi Germany
W
Declaration
cells: 1943-10-13
Italy
Nazi Germany
W[3]
Italy had changed side after the fall of Mussolini. The Declaration of War was given by Pietro Badoglio to the German ambassador in Madrid.[3]
Declaration
cells: 1943-11-26
Colombia
Nazi Germany
W
Declaration
cells: 1944-01-17
Free France
Italian Social Republic
A
Invasion
cells: 1944-01-27
Liberia
Nazi Germany  Japan
W
Declaration
cells: 1944-06-06
France
Nazi Germany
A
Invasion
cells: 1944-07-25
France
Japan
A
Invasion
cells: 1944-08-25
Romania
Nazi Germany  Hungary
W
Romania switched sides
Declaration
cells: 1944-09-05
Soviet Union
Bulgaria
W
Declaration
cells: 1944-09-08
Bulgaria
Nazi Germany
W
Bulgaria switched sides
Declaration
cells: 1944-09-15
Nazi Germany
Finland
A
Lapland War
cells: 1944-09-23
Philippines
United States  United Kingdom
W[11]
Lapland War
cells: 1944-12-31
Hungary
Nazi Germany
W[12]
Hungary switched sides
Declaration
cells: 1945-02-02
Ecuador
Nazi Germany  Japan
W
Ecuadorian declaration
cells: 1945-02-07
Argentina  Paraguay
Nazi Germany  Japan
W
Argentinean declaration Paraguayan declaration
cells: 1942-02-12
Peru
Nazi Germany  Japan
W
Declaration
cells: 1945-02-15
Venezuela  Uruguay
Nazi Germany  Japan
W
Venezuelan declaration Uruguayan declaration
cells: 1945-02-21
San Marino
Nazi Germany
W
Declaration
cells: 1945-02-23
Turkey
Nazi Germany  Japan
W
Declaration
cells: 1945-02-24
Egypt
Nazi Germany  Japan
W
Declaration
cells: 1945-02-26
Syria  Lebanon
Nazi Germany  Japan
W
Declaration
cells: 1945-04-01
Saudi Arabia
Japan
W
Declaration
cells: 1945-04-03
Finland
Nazi Germany
W
Finland switched sides
Lapland War
cells: 1945-04-11
Chile
Japan
W
Declaration
cells: 1945-07-06
Brazil
Japan
W
Declaration
cells: 1945-07-14
Italy
Japan
W
Declaration
cells: 1945-08-08
Soviet Union
Japan
W[3]
Last outbreak of war during the entire Second World War.
Declaration
cells: 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

Questions about this table:
originalText: who did russia declare war on in ww2
answer: answerTexts: Bulgaria
Japan