1921

1921 (MCMXXI) was a common year starting on Saturday in the Gregorian calendar and a common year starting on Friday in the Julian calendar.

 Events 
 Albert Einstein receives the Nobel Prize in Physics.
 Partition of Ireland (May 3rd)
 Tulsa Race Massacre in Oklahoma, United States (May 31st-June 1st)
 Karl Gareis is murdered in Munich, Germany (June 9th)
 Insulin is invented in Canada by Frederick Banting and Charles Best (July 27th)
 Matthias Erzberger is murdered in Germany (August 25th)
 A hurricane devastates Tampa Bay, Florida (October 20th-October 30th)
 Anglo-Irish Treaty signed (December 6th)

 Births 
 January 
 January 5 – Jean, Grand Duke of Luxembourg (d. 2019)
 January 17 – Antonio Prohias Cuban-American cartoonist (d. 1998)
 January 19 – Patricia Highsmith, American writer (d. 1995)
 January 27 - Donna Reed, American actress (d. 1986)
 January 29 – Mustafa Ben Halim, 3rd Prime Minister of Libya (d. 2021)
 January 31 – Carol Channing, American actress and singer (d. 2019)

 February 
 February 4 – Betty Friedan, American feminist, activist, and writer (d. 2006)
 February 4 – K. R. Narayanan, President of India (d. 2005)
 February 8 – Lana Turner, American actress (d. 1995)
 February 16 - Hua Guofeng, Chairman of the Communist Party of China (d. 2008)
 February 20 – Suharto, 2nd President of Indonesia (d. 2008)
 February 22 - Jean-Bédel Bokassa, 2nd President of the Central African Republic (d. 1996)

 March 
 March 21 – Abdul Salam Arif, 2nd President of Iraq (d. 1966)
 March 24 – Vasily Smyslov, Russian chess player (d. 2010)
 March 25 – Nancy Kelly, American actress (d. 1995)

 April 
 April 9 - Yitzhak Navon, 5th President of Israel (d. 2015)
 April 14 – Thomas Schelling, American economist (d. 2016)
 April 25 – Karel Appel, Belgian artist (d. 2006)

 May 
 May 2 – Satyajit Ray, Indian movie maker (d. 1992)
 May 3 – Sugar Ray Robinson, American boxer (d. 1989)
 May 21 – Andrei Sakharov, Soviet physicist and activist (d. 1989)
 May 25 – Jack Steinberger, German-American physicist (d. 2020)

 June 
 June 10 – Prince Philip, Duke of Edinburgh, member of the British royal family, husband of Queen Elizabeth II (d. 2021)
 June 21 – Jane Russell, American actress (d. 2011)

 July 
 July 6 – Nancy Reagan, First Lady of the United States (d. 2016)
 July 14 – Geoffrey Wilkinson, English chemist (d. 1996)
 July 18 – John Glenn, American astronaut and politician (d. 2016)
 July 24 – Giuseppe Di Stefano, Italian operatic tenor (d. 2008)

 August 
 August 8 – Esther Williams, American swimmer and actress (d. 2013)

 September 
 September 1 – Willem Frederik Hermans, Dutch writer (d. 1995)
 September 30 – Deborah Kerr, Scottish actress (d. 2007)
 September 30 – Sagramor de Scuvero Brandão, Brazilian actress, radio personality and councillor (d. 1995)

 October 
 October 4 – Francisco Morales-Bermúdez, 112th Prime Minister and 51st President of Peru (d. 2022)
 October 19 – Gunnar Nordahl, Swedish footballer (d. 1995)

 November 
 November 27 – Alexander Dubček, First Secretary of the Communist Party of Czechoslovakia (d. 1992)

 December 
 December 26 – Steve Allen, American actor, comedian, composer, and writer (d. 2000)

 Deaths 

 January 

 February 

 March 
 March 1 – King Nicholas I of Montenegro (b. 1841)

 April 

 May 

 June 

 June 9 – Karl Gareis, German legal scholar (b.1889)

 July 
 July 4 – Antoni Grabowski, early proponent of Esperanto (b. 1857)

 August 
 August 2 – Enrico Caruso, Italian operatic tenor (b. 1873)
 August 16 – Peter I of Serbia (b. 1844)
 August 25 – Matthias Erzberger, former German minister of finance (b. 1875)

 September 

 October 

 November 

 December 

 Sports 
Kentucky Derby winner, Behave Yourself