Sovereign States
editA
edit- Abkhazia - Socialist Soviet Republic of Abkhazia (to March 12)
- Afghanistan - Emirate of Afghanistan
- Albania - Principality of Albania
- Andorra - Principality of Andorra
- Argentina - Argentine Republic
- Armenia - Armenian Socialist Soviet Republic (to March 12)
- File:Flag of Asir.svg Asir - Emirate of Asir
- Australia - Commonwealth of Australia
- Austria - Federal State of Austria
- Azerbaijan - Azerbaijan Socialist Soviet Republic (to March 12)
B
edit- Belgium - Kingdom of Belgium
- Bolivia - Republic of Bolivia
- Brazil - Republic of the United States of Brazil
- Bulgaria - Kingdom of Bulgaria
C
edit- Canada - Dominion of Canada
- Central America - Federation of Central America (to February 7)
- Chile - Republic of Chile
- China - Republic of China
- Colombia - Republic of Colombia
- Costa Rica - Republic of Costa Rica
- Cuba - Republic of Cuba
- Czechoslovakia - Czechoslovak Republic
D
edit- Danzig - Free City of Danzig
- Denmark - Kingdom of Denmark
- Dominican Republic
E
edit- Ecuador - Republic of Ecuador
- Egypt - Kingdom of Egypt (from November 11)
- El Salvador - Republic of El Salvador (from February 4)
- Estonia - Republic of Estonia
- Ethiopia - Ethiopian Empire
F
editG
edit- Germany - German Reich
- Greece - Kingdom of Greece
- Guatemala - Republic of Guatemala (from January 14)
H
edit- Haiti - Republic of Haiti
- Hejaz - Kingdom of Hejaz
- Honduras - Republic of Honduras (from February 7)
- Hungary - Kingdom of Hungary
I
editJ
edit- Japan - Empire of Japan
L
edit- Latvia - Republic of Latvia
- Liberia - Republic of Liberia
- Liechtenstein - Principality of Liechtenstein
- Lithuania - Republic of Lithuania
- Luxembourg - Grand Duchy of Luxembourg
M
edit- Mexico - United Mexican States
- Monaco - Principality of Monaco
- Mongolia - Mongolian People's Government
N
edit- Nejd - Sultanate of Nejd
- Netherlands - Kingdom of the Netherlands
- Newfoundland - Dominion of Newfoundland
- New Zealand - Dominion of New Zealand
- Nicaragua - Republic of Nicaragua
- Norway - Kingdom of Norway
O
edit- Ottoman Empire - Sublime Ottoman State
P
edit- Panama - Republic of Panama
- Paraguay - Republic of Paraguay
- Persia - Persian Empire
- Peru - Peruvian Republic
- Poland - Republic of Poland
- Portugal - Portuguese Republic
R
editS
edit- San Marino - Most Serene Republic of San Marino
- Serbs, Croats and Slovenes - Kingdom of Serbs, Croats, and Slovenes
- Siam - Kingdom of Siam
- South Africa - Union of South Africa
- Soviet Union - Union of Soviet Socialist Republics (from December 30)
- Spain - Kingdom of Spain
- Sweden - Kingdom of Sweden
- Switzerland - Swiss Confederation
T
edit- Transcaucasia - Transcaucasian Socialist Federative Soviet Republic (from March 12 to December 30)
U
edit- United Kingdom - United Kingdom of Great Britain and Ireland
- United States - United States of America
- Uruguay - Eastern Republic of Uruguay
V
edit- Venezuela - United States of Venezuela
Y
edit- Yemen - Mutawakkilite Kingdom of Yemen
Other states
edit- Bottleneck - Free State Bottleneck
- Bukharan - Bukharan People's Soviet Republic
- Byelorussia - Byelorussian Socialist Soviet Republic (to December 30)
- Central Lithuania - Republic of Central Lithuania (to March 24)
- Far Eastern Republic (to November 15)
- Georgia, Soviet - Socialist Soviet Republic of Georgia (to March 12)
- Ireland - Irish Republic (to December 6)
- Khorezm - Khorezm People's Soviet Republic
- Kurdistan - Kingdom of Kurdistan (from September)
- North Caucasian Emirate
- Rif - Confederal Republic of the Tribes of the Rif
- Tannu Tuva - People's Republic of Tannu Tuva
- Tavolara - Kingdom of Tavolara
- Tibet
- Ukraine, Soviet - Ukrainian Socialist Soviet Republic (to December 30)
League of Nations Mandates
edit- British Togoland (administered by the United Kingdom from July 20)
- Cameroons - British Cameroons (administered by the United Kingdom from July 20)
- Cameroun (administered by France from July 20)
- French Togoland (administered by France from July 20)
- Mesopotamia - British Mandate of Mesopotamia (administered by the United Kingdom)
- Nauru (administered by Australia, New Zealand and the United Kingdom)
- New Guinea - Territory of New Guinea (administered by Australia)
- Ruanda-Urundi (administered by Belgium from November 1)
- South Pacific Mandate (administered by Japan)
- South-West Africa (administered by South Africa from October 1)
- Tanganyika - Tanganyika Territory (administered by the United Kingdom from July 20)
- Western Samoa (administered by New Zealand)