January 2 – The De Young Museum opens in Golden Gate Park, San Francisco
January 20 – British K-class submarine HMS K5 sinks in the English Channel. All 56 on board die.
January 21 – The film The Kid, written, produced, directed by and starring Charlie Chaplin, with Jackie Coogan, is released in the United States.
February 12 – The Democratic Republic of Georgia is invaded by forces of Bolshevist Russia.
February 21 – Rezā Khan and Zia’eddin Tabatabaee stage a coup d’état in Iran.
February 28 – The Kronstadt rebellion is initiated by sailors of the Soviet Navy’s Baltic Fleet.
March 4 – Warren G. Harding is sworn in as the 29th President of the United States.
March 8 – Spanish Premier Eduardo Dato e Iradier is assassinated while exiting the parliament building in Madrid.
March 13 – The Russian White Army captures Mongolia from China. Roman von Ungern-Sternberg declares himself ruler.
April 11 – The Emirate of Transjordan is created, with Abdullah I as emir.
May 1–7 – Riots at Jaffa, Mandatory Palestine result in 47 Jewish and 48 Arab deaths.
May 25 – The Irish Republican Army occupies and burns The Custom House in Dublin. Five IRA men are killed, and over 80 are captured by the British Army.
May 31–June 1 – Mobs of white residents attack black residents and businesses in Tulsa, Oklahoma. Between 100 and 300 are killed.
June 28 – The Constitutional Assembly of the Kingdom of Serbs, Croats and Slovenes passes the Vidovdan Constitution, despite a boycott of the vote by the communists, and Croat and Slovene parties.
July 1 – The Communist Party of China (CPC) is founded.
July 11 – The Red Army captures Mongolia from the White Army, and establishes the Mongolian People’s Republic.
July 21 – At The Battle of Annual, Spanish troops are dealt a crushing defeat, at the hands of Abd el-Krim.
July 29 – Adolf Hitler becomes Führer of the Nazi Party.
August 23 – King Faisal I of Iraq is crowned in Baghdad.
August 24 – R38-class airship ZR-2 explodes on her fourth test flight near Kingston upon Hull, England, killing 44 of the 49 Anglo-American crew on board.
September 7 – In Atlantic City, New Jersey, the first Miss America Pageant is held.
September 13 – White Castle hamburger restaurant opens in Wichita, Kansas, the foundation of the world’s first fast food chain.
September 21 – The Oppau explosion occurs at BASF’s nitrate factory in Oppau, Germany. 500–600 are killed.
October 13 – The Treaty of Kars is signed between Turkey and the Soviet Socialist Republics of Armenia, Azerbaijan and Georgia, establishing the boundaries of the south Caucasus.
October 19 – The ‘Bloody Night’ (Noite Sangrenta) massacre in Lisbon claims the lives of Portuguese Prime-Minister António Granjo and other politicians.
November 9 – The National Fascist Party (Partito Nazionale Fascista or PNF) is founded in Italy.
November 11 – During an Armistice Day ceremony at Arlington National Cemetery, the Tomb of the Unknown Soldier is dedicated by Warren G. Harding, President of the United States.
November – Hyperinflation is rampant in Germany, where 263 marks are now needed to buy a single American dollar, more than 20 times greater than the 12 marks needed in April 1919.
December 6 – The Anglo-Irish Treaty establishing the Irish Free State is signed in London.
December 13 – In the Four-Power Treaty on Insular Possessions, Japan, the United States, United Kingdom, and France agree to recognize the status quo in the Pacific.
December 23 – Visva-Bharati College is founded by Rabindranath Tagore in Santiniketan, Bengal Presidency, British India.