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.

• 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)

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

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

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

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

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

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

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

• 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)

• Kentucky Derby winner, Behave Yourself