October 21 is the 294th day of the year (295th in leap years) in the Gregorian calendar; 71 days remain until the end of the year.

• 1096 – A Seljuk Turkish army successfully fights off the People's Crusade at the Battle of Civetot.
• 1097 – First Crusade: Crusaders led by Godfrey of Bouillon, Bohemund of Taranto, and Raymond IV, Count of Toulouse, begin the Siege of Antioch.
• 1392 – Japanese Emperor Go-Kameyama abdicates in favor of rival claimant Go-Komatsu.
• 1512 – Martin Luther joins the theological faculty of the University of Wittenberg.
• 1520 – João Álvares Fagundes discovers the islands of Saint Pierre and Miquelon, bestowing them their original name of "Islands of the 11,000 Virgins".
• 1600 – Tokugawa Ieyasu defeats the leaders of rival Japanese clans in the Battle of Sekigahara and becomes shōgun of Japan.

• 1774 – The flag of Taunton, Massachusetts is the first to include the word "Liberty".
• 1797 – In Boston Harbor, the 44-gun United States Navy frigate USS Constitution is launched.
• 1805 – Napoleonic Wars: A British fleet led by Lord Nelson defeats a combined French and Spanish fleet under Admiral Villeneuve in the Battle of Trafalgar.
• 1824 – Portland cement is patented.
• 1854 – Florence Nightingale and a staff of 38 nurses are sent to the Crimean War.
• 1861 – American Civil War: Union forces under Colonel Edward Baker are defeated by Confederate troops in the second major battle of the war.
• 1867 – The Medicine Lodge Treaty is signed by southern Great Plains Indian leaders. The treaty requires Native American Plains tribes to relocate to a reservation in the western Indian Territory.
• 1879 – Thomas Edison applies for a patent for his design for an incandescent light bulb.
• 1888 – The Swiss Social Democratic Party is founded.
• 1892 – Opening ceremonies for the World's Columbian Exposition are held in Chicago, though because construction was behind schedule, the exposition did not open until May 1, 1893.
• 1895 – The capitulation of Tainan completes the Japanese conquest of Taiwan.

• 1907 – The 1907 Qaratog earthquake hits the borders of Uzbekistan and Tajikistan, killing between 12,000 and 15,000 people.
• 1910 – HMS Niobe arrives in Halifax Harbour to become the first ship of the Royal Canadian Navy.
• 1912 – First Balkan War: The Greek navy completes the capture of the island of Lemnos for use as a forward base against the Dardanelles.^[1]
• 1921 – President Warren G. Harding delivers the first speech by a sitting U.S. president against lynching in the Deep South.
• 1931 – A secret society in the Imperial Japanese Army launches an abortive coup d'état attempt.
• 1940 – The first edition of the Ernest Hemingway novel For Whom the Bell Tolls is published.
• 1941 – World War II: The Kragujevac massacre against Serbian men and boys takes place.^[2]
• 1943 – World War II: The Provisional Government of Free India is formally established in Japanese-occupied Singapore.
• 1944 – World War II: The first kamikaze attack damages HMAS Australia as the Battle of Leyte Gulf begins.
• 1944 – World War II: The Nemmersdorf massacre against German civilians takes place.
• 1944 – World War II: The city of Aachen falls to American forces after three weeks of fighting, the first German city to fall to the Allies.
• 1945 – In the 1945 French legislative election French women vote for the first time.
• 1950 – Korean War: Heavy fighting begins between British and Australian forces and North Koreans during the Battle of Yongju.
• 1956 – The Mau Mau Uprising in Kenya is defeated.
• 1959 – In New York City, the Solomon R. Guggenheim Museum opens to the public.
• 1959 – President Dwight D. Eisenhower approves the transfer of all US Army space-related activities to NASA, including most of the Army Ballistic Missile Agency.
• 1965 – Comet Ikeya–Seki approaches perihelion, passing 450,000 kilometers (279,617 miles) from the sun.
• 1966 – A colliery spoil tip slips onto houses and a school in the village of Aberfan in Wales, killing 144 people, 116 of whom were schoolchildren.^[3]
• 1967 – The National Mobilization Committee to End the War in Vietnam organizes a march of fifty thousand people from the Lincoln Memorial to the Pentagon.
• 1969 – The 1969 Somali coup d'état establishes a Marxist–Leninist administration.
• 1971 – A gas explosion kills 22 people at a shopping centre near Glasgow, Scotland.
• 1973 – Fred Dryer of the Los Angeles Rams becomes the first player in NFL history to score two safeties in the same game.
• 1978 – Australian civilian pilot Frederick Valentich vanishes over the Bass Strait south of Melbourne, after reporting contact with an unidentified aircraft.^[4]
• 1979 – Moshe Dayan resigns from the Israeli government because of strong disagreements with Prime Minister Menachem Begin over policy towards the Arabs.
• 1981 – Andreas Papandreou becomes Prime Minister of Greece, ending an almost 50-year-long system of power dominated by conservative forces.
• 1983 – The metre is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.
• 1984 – Niki Lauda claims his third and final Formula One Drivers' Championship Title by half a point ahead of McLaren team-mate Alain Prost at the Portuguese Grand Prix.^[5]
• 1986 – In Lebanon, pro-Iran kidnappers claim to have abducted American writer Edward Tracy (he is released in August 1991).
• 1987 – The Jaffna hospital massacre is carried out by Indian peacekeeping forces in Sri Lanka, killing 70 Tamil patients, doctors and nurses.
• 1989 – In Honduras, 131 people are killed when a Boeing 727 crashes on approach to Toncontín International Airport near the nation's capital Tegucigalpa.^[6]
• 1994 – North Korea and the United States sign an Agreed Framework that requires North Korea to stop its nuclear weapons program and agree to inspections.
• 1994 – In Seoul, South Korea, 32 people are killed when a span of the Seongsu Bridge collapses.^[7]
• 2005 – Images of the dwarf planet Eris are taken and subsequently used in documenting its discovery.
• 2011 – Iraq War: President Barack Obama announces that the withdrawal of United States troops from Iraq will be complete by the end of the year.^[8]
• 2019 – Thirty people are killed in a fiery bus crash in western Democratic Republic of the Congo.^[9]
• 2019 – In Canada, the 2019 Canadian federal election ends, resulting in incumbent Prime Minister Justin Trudeau remaining in office, albeit with the Liberal Party in a minority government.^[10][11]
• 2021 – A shooting occurs on the set of the film Rust, in which actor Alec Baldwin discharged a prop weapon which had been loaded, killing the director of photography, Halyna Hutchins, and injuring director Joel Souza.^[12]

• 1328 – Hongwu Emperor of China (d. 1398)
• 1409 – Alessandro Sforza, Italian condottiero (d. 1473)^[13]
• 1449 – George Plantagenet, 1st Duke of Clarence, Irish-English son of Cecily Neville, Duchess of York (d. 1478)
• 1527 – Louis I, Cardinal of Guise (d. 1578)
• 1536 – Joachim Ernest, Prince of Anhalt (d. 1586)
• 1581 – Domenichino, Italian painter (d. 1641)

• 1650 – Jean Bart, French admiral (d. 1702)
• 1658 – Henri de Boulainvilliers, French nobleman (d. 1722)
• 1675 – Emperor Higashiyama of Japan (d. 1710)
• 1687 – Nicolaus I Bernoulli, Swiss mathematician and theorist (d. 1759)
• 1712 – James Steuart, Scottish economist and author (d. 1780)^[14]
• 1725 – Franz Moritz von Lacy, Austrian field marshal (d. 1801)
• 1757 – Pierre Augereau, French general (d. 1816)
• 1762 – Herman Willem Daendels, Dutch general, lawyer, and politician, 36th Governor-General of the Dutch East Indies (d. 1818)
• 1772 – Samuel Taylor Coleridge, English poet, philosopher, and critic (d. 1834)
• 1775 – Giuseppe Baini, Italian priest, composer, and critic (d. 1844)
• 1790 – Alphonse de Lamartine, French poet and politician, French Head of State (d. 1869)
• 1809 – James Clark, American Jesuit (d. 1885)^[15]
• 1811 – Filippo Colini, Italian operatic baritone (d. 1863)
• 1821 – Sims Reeves, English tenor and actor (d. 1900)
• 1833 – Alfred Nobel, Swedish chemist and engineer, invented dynamite and founded the Nobel Prize (d. 1896)
• 1845 – Will Carleton, American poet and journalist (d. 1912)
• 1847 – Giuseppe Giacosa, Italian poet and playwright (d. 1906)
• 1851 – George Ulyett, English cricketer and footballer (d. 1898)
• 1868 – Ernest Swinton, British Army officer (d. 1951)
• 1874 – Tan Kah Kee, Chinese businessman, community leader, communist and philanthropist (d. 1961)
• 1877 – Oswald Avery, Canadian-American physician and microbiologist (d. 1955)
• 1884 – Claire Waldoff, German singer and actress (d. 1957)
• 1886 – Eugene Burton Ely, American soldier and pilot (d. 1911)
• 1887 – Krishna Singh, Indian lawyer and politician, 1st Chief Minister of Bihar (d. 1961)
• 1894 – Edogawa Ranpo, Japanese author and critic (d. 1965)
• 1895 – Paavo Johansson, Finnish javelin thrower and decathlete (d. 1983)
• 1895 – Edna Purviance, American actress (d. 1958)
• 1896 – Esther Shumiatcher-Hirschbein, Russian-Canadian poet and screenwriter (d. 1985)
• 1898 – Eduard Pütsep, Estonian wrestler and actor (d. 1960)
• 1900 – Andrée Boisson, French Olympic fencer (d. 1973)

• 1902 – Eddy Hamel, American footballer (d. 1943)^[16]
• 1907 – Nikos Engonopoulos, Greek painter and poet (d. 1985)
• 1908 – Niyazi Berkes, Cypriot-English sociologist and academic (d. 1988)
• 1911 – Mary Blair, American illustrator and animator (d. 1978)
• 1912 – Don Byas, American saxophonist and educator (d. 1972)
• 1912 – Alfredo Pián, Argentinian race car driver (d. 1990)
• 1912 – Georg Solti, Hungarian-English conductor and director (d. 1997)
• 1914 – Martin Gardner, American mathematician and author (d. 2010)
• 1915 – Owen Bradley, American country music record producer (d. 1998)
• 1917 – Dizzy Gillespie, American trumpet player, composer, and bandleader (d. 1993)^[17]
• 1918 – Milton Himmelfarb, American sociologist and author (d. 2006)
• 1918 – Albertina Sisulu, South African anti-apartheid activist (d. 2011)
• 1919 – Jim Wallwork, English-Canadian sergeant and pilot (d. 2013)
• 1921 – Malcolm Arnold, English composer (d. 2006)
• 1921 – Bruce Beeby, Australian-English actor (d. 2013)
• 1921 – Robert Clothier, Canadian actor (d. 1999)
• 1921 – Jim Shumate, American fiddler and composer (d. 2013)
• 1921 – Ingrid van Houten-Groeneveld, Dutch astronomer and academic (d. 2015)
• 1922 – Liliane Bettencourt, French businesswoman and philanthropist (d. 2017)
• 1923 – Samuel Khachikian, Iranian director, screenwriter, and author (d. 2001)
• 1924 – Joyce Randolph, American actress (d. 2024)^[18]
• 1924 – Julie Wilson, American actress and singer (d. 2015)
• 1925 – Celia Cruz, Cuban-American singer (d. 2003)^[17]
• 1925 – Virginia Zeani, Romanian soprano and educator (d. 2023)
• 1926 – Bob Rosburg, American golfer (d. 2009)
• 1926 – Leonard Rossiter, English actor (d. 1984)
• 1927 – Fritz Wintersteller, Austrian mountaineer (d. 2018)
• 1927 – Howard Zieff, American director and photographer (d. 2009)
• 1928 – Whitey Ford, American baseball player and coach (d. 2020)^[17]
• 1928 – Eudóxia Maria Froehlich, Brazilian zoologist (d. 2015)
• 1928 – Vern Mikkelsen, American basketball player and coach (d. 2013)
• 1929 – Pierre Bellemare, French radio and television host (d. 2018)
• 1929 – Fritz Hollaus, Austrian footballer (d. 1994)
• 1929 – Ursula K. Le Guin, American author and critic (d. 2018)^[17]
• 1929 – George Stinney Jr., wrongfully convicted African-American inmate; second youngest person in the U.S. to be executed (d. 1944)^[19][20][21]
• 1930 – Ivan Silayev, Russian engineer and politician, 19th Prime Minister of Russia (d. 2023)
• 1931 – Shammi Kapoor, Indian actor and director (d. 2011)
• 1931 – Jim Parks Jr., English cricketer and manager (d. 2022)
• 1932 – Pál Csernai, Hungarian footballer and manager (d. 2013)
• 1933 – Maureen Duffy, English author, poet, playwright and activist^[22]
• 1933 – Francisco Gento, Spanish footballer and manager (d. 2022)
• 1935 – Derek Bell, Irish harp player, pianist, and songwriter (d. 2002)
• 1935 – Mel Street, American country music singer-songwriter and guitarist (d. 1978)
• 1937 – Said Afandi al-Chirkawi, Russian spiritual leader and scholar (d. 2012)
• 1937 – Hank Nelson, Australian historian and academic (d. 2012)
• 1938 – Carl Brewer, Canadian ice hockey player (d. 2001)
• 1940 – Geoffrey Boycott, English cricketer and sportscaster
• 1940 – Frances FitzGerald, American journalist and author
• 1940 – Rhoda Gemignani, American actress
• 1940 – Manfred Mann, South African-English keyboard player and producer^[23]
• 1940 – Marita Petersen, Faroese educator and politician, Prime Minister of the Faroe Islands (d. 2001)
• 1941 – Steve Cropper, American guitarist, songwriter, producer, and actor^[23]
• 1942 – Elvin Bishop, American singer-songwriter and guitarist
• 1942 – Allan Grice, Australian race car driver and politician
• 1942 – Lou Lamoriello, American ice hockey player, coach, and manager
• 1942 – Judy Sheindlin, American judge and television host^[23]
• 1942 – Christopher A. Sims, American economist and statistician, Nobel Prize laureate
• 1942 – John Stevens, Baron Stevens of Kirkwhelpington, English police officer and academic
• 1943 – Tariq Ali, Pakistani historian and author
• 1943 – Ron Elliott, American singer-songwriter, guitarist, and composer
• 1944 – Mandy Rice-Davies, English model and actress (d. 2014)
• 1944 – Michael Tugendhat, English lawyer and judge
• 1945 – Everett McGill, American actor^[23]
• 1945 – Nikita Mikhalkov, Russian filmmaker
• 1945 – Michael White, English journalist
• 1946 – Jane Heal, English philosopher and academic
• 1946 – Jim Hill, American football player and sportscaster
• 1946 – Lux Interior, American singer-songwriter (d. 2009)
• 1946 – Lee Loughnane, American singer-songwriter and trumpet player^[23]
• 1948 – Shaye J. D. Cohen, American historian and academic
• 1948 – Allen Henry Vigneron, American archbishop
• 1949 – Michel Brière, Canadian ice hockey player (d. 1971)
• 1949 – Mike Keenan, Canadian ice hockey player and coach
• 1949 – Benjamin Netanyahu, Israeli captain and politician, 9th Prime Minister of Israel^[17]
• 1950 – Ronald McNair, American physicist and astronaut (d. 1986)^[24]
• 1950 – Leela Vernon, Belizean musician and cultural conservationist (d. 2017)^[25]
• 1952 – Patti Davis, American actress and author
• 1952 – Allen Hoey, American poet and author (d. 2010)
• 1952 – Brent Mydland, German-American keyboard player (d. 1990)
• 1953 – Charlotte Caffey, American guitarist and songwriter^[23]
• 1953 – Eric Faulkner, Scottish singer-songwriter and guitarist
• 1953 – Keith Green, American singer-songwriter, pianist, and minister (d. 1982)
• 1953 – Marc Johnson, American bassist, composer, and bandleader
• 1953 – Peter Mandelson, English journalist and politician, Secretary of State for Northern Ireland
• 1954 – Brian Tobin, Canadian journalist and politician, 6th Premier of Newfoundland
• 1955 – Dick DeVos, American businessman
• 1955 – Catherine Hardwicke, American film director, producer, and screenwriter^[23]
• 1955 – Fred Hersch, American pianist and composer
• 1955 – Rich Mullins, American singer-songwriter (d. 1997)
• 1956 – Carrie Fisher, American actress and screenwriter (d. 2016)^[17]
• 1956 – Mike Tully, American pole vaulter
• 1957 – Julian Cope, English singer-songwriter^[23]
• 1957 – Irene Edgar, Scottish lawn bowler^[26]
• 1957 – Wolfgang Ketterle, German physicist and academic, Nobel Prize laureate
• 1957 – Steve Lukather, American singer-songwriter, guitarist, and producer^[23]
• 1958 – Andre Geim, Russian-English physicist and academic, Nobel Prize laureate
• 1959 – George Bell, Dominican baseball player
• 1959 – Rose McDowall, Scottish singer-songwriter and guitarist
• 1959 – Andy Picheta, English director, producer, and screenwriter
• 1959 – Kevin Sheedy, Welsh-Irish footballer and manager
• 1959 – Ken Watanabe, Japanese actor and producer^[23]
• 1960 – Melora Walters, American actress, director, and writer^[23]
• 1962 – David Campese, Australian rugby player and coach
• 1964 – Jon Carin, American singer-songwriter, guitarist, and producer
• 1965 – Ion Andoni Goikoetxea, Spanish footballer and manager
• 1965 – Horace Hogan, American wrestler
• 1965 – Hisashi Imai, Japanese singer-songwriter and guitarist
• 1966 – Phillip Price, Welsh golfer
• 1966 – Igor Prins, Estonian footballer and manager
• 1966 – Arne Sandstø, Norwegian footballer and manager
• 1967 – Georgi Dakov, Bulgarian high jumper (d. 1996)
• 1967 – Paul Ince, English footballer and manager
• 1967 – Gavin Lovegrove, New Zealand javelin thrower and graphic designer
• 1968 – Alexandros Alexandris, Greek footballer and manager
• 1968 – Kerstin Andreae, German politician
• 1969 – Michael Hancock, Australian rugby league player
• 1969 – Mo Lewis, American football player
• 1970 – Louis Koo, Hong Kong actor and singer
• 1971 – Hal Duncan, Scottish author and poet
• 1971 – Damien Martyn, Australian cricketer
• 1971 – Nick Oliveri, American singer-songwriter and bass player^[23]
• 1971 – Conor O'Shea, Irish rugby player and coach
• 1971 – Paul Telfer, Scottish footballer and coach
• 1971 – Thomas Ulsrud, Norwegian curler
• 1972 – Ashutosh Agashe, Indian businessman and cricketer
• 1972 – Matthew Friedberger, American singer-songwriter and guitarist
• 1972 – Orlando Thomas, American football player (d. 2014)
• 1972 – Evhen Tsybulenko, Ukrainian scholar and academic
• 1973 – Lera Auerbach, Russian-American pianist and composer
• 1973 – Charlie Lowell, American pianist and songwriter^[23]
• 1974 – Costel Busuioc, Romanian tenor
• 1975 – Toby Hall, American baseball player
• 1975 – Henrique Hilário, Portuguese footballer
• 1976 – Henrik Gustavsson, Swedish footballer
• 1976 – Jeremy Miller, American actor and singer^[23]
• 1976 – Lavinia Miloșovici, Romanian gymnast
• 1976 – Josh Ritter, American singer-songwriter and guitarist
• 1976 – Andrew Scott, Irish actor^[23]
• 1976 – Mélanie Turgeon, Canadian skier
• 1978 – Will Estes, American actor^[23]
• 1978 – Joey Harrington, American football player and sportscaster
• 1978 – Henrik Klingenberg, Finnish singer and keyboard player
• 1978 – Michael McMillian, American actor^[23]
• 1979 – Khalil Greene, American baseball player
• 1979 – Gabe Gross, American baseball player
• 1980 – Kim Kardashian, American reality television personality, actress, model, businesswoman and socialite^[23]
• 1980 – Brian Pittman, American bass player
• 1981 – Martin Castrogiovanni, Argentinian-Italian rugby player
• 1981 – Nemanja Vidić, Serbian footballer
• 1982 – Matt Dallas, American actor^[17]
• 1982 – Jim Henderson, American baseball player
• 1982 – Antony Kay, English footballer
• 1982 – Hari Kondabolu, American comedian, actor, and podcaster
• 1982 – Ray Ventrone, American football player
• 1982 – Lee Chong Wei, Malaysian badminton player
• 1982 – James White, American basketball player
• 1983 – Casey Fien, American baseball player
• 1983 – Zack Greinke, American baseball player
• 1983 – Brent Hayden, Canadian swimmer^[27]
• 1983 – Gonzalo Klusener, Argentinian footballer
• 1983 – Andy Marte, Dominican baseball player (d. 2017)
• 1983 – Amber Rose, American model^[17]
• 1983 – Chris Sherrington, English-Scottish martial artist
• 1983 – Charlotte Sullivan, Canadian actress^[23]
• 1983 – Ninet Tayeb, Israeli singer
• 1983 – Shelden Williams, American basketball player
• 1984 – Anna Bogdanova, Russian heptathlete
• 1984 – Tom Brandstater, American football player
• 1984 – Kenny Cooper, American soccer player
• 1984 – Anouk Leblanc-Boucher, Canadian speed skater
• 1984 – José Lobatón, Venezuelan baseball player
• 1984 – Marvin Mitchell, American football player
• 1984 – Kieran Richardson, English footballer
• 1985 – Simone Bracalello, Italian footballer
• 1985 – Dean Collis, Australian rugby league player
• 1986 – Almen Abdi, Swiss footballer
• 1986 – Chibuzor Chilaka, Nigerian footballer
• 1986 – Scott Rendell, English footballer
• 1987 – Tonje Brenna, Norwegian politician^[28]
• 1987 – Justin De Fratus, American baseball player
• 1987 – Andrey Grechin, Russian swimmer
• 1988 – Ricki Olsen, Danish footballer
• 1988 – Glen Powell, American actor^[23]
• 1988 – Daniel Schorn, Austrian cyclist
• 1989 – Mads Dahm, Norwegian footballer
• 1989 – Festus Ezeli, Nigerian-American basketball player^[29]
• 1989 – Luke Murphy, English footballer
• 1989 – Jonathan Viera, Spanish footballer
• 1989 – Sam Vokes, English-Welsh footballer
• 1990 – Bengali-Fodé Koita, French footballer
• 1990 – Mathieu Peybernes, French footballer
• 1990 – Ricky Rubio, Spanish basketball player
• 1990 – Kristján Þórður Snæbjarnarson, Icelandic politician^[30]
• 1991 – Alexander Burmistrov, Russian ice hockey player^[31]
• 1991 – Tom Eastman, English footballer
• 1991 – Geoffry Hairemans, Belgian footballer
• 1991 – Rob Keogh, English cricketer
• 1991 – Vadaine Oliver, English footballer
• 1991 – Harry Pell, English footballer
• 1992 – Natasha Bassett, Australian actress^[23]
• 1992 – Marzia Kjellberg, Italian businessperson and former YouTuber
• 1992 – Damion Lee, American basketball player^[32]
• 1992 – Bernard Tomic, German-Australian tennis player^[33]
• 1993 – Kane Brown, American singer and songwriter^[34]
• 1995 – Cameron Burgess, Scottish-Australian footballer
• 1995 – Doja Cat, American rapper, singer and songwriter^[35]
• 1995 – Antoinette Guedia Mouafo, Cameroonian swimmer

• 645 – Zhenzhu Khan, khan of Xueyantuo
• 1023 – Gero, Archbishop of Magdeburg
• 1096 – Walter Sans Avoir, a leader of the First Crusade
• 1125 – Cosmas of Prague, Bohemian priest and historian (b. 1045)
• 1204 – Robert de Beaumont, 4th Earl of Leicester, English politician
• 1221 – Alix, Duchess of Brittany (b. 1201)
• 1266 – Birger Jarl, Swedish politician (b. 1210)
• 1314 – Geoffrey de Geneville, 1st Baron Geneville
• 1422 – Charles VI of France (b. 1368)^[36]
• 1500 – Emperor Go-Tsuchimikado of Japan (b. 1442)
• 1505 – Paul Scriptoris, German mathematician and educator (b. 1460)
• 1556 – Pietro Aretino, Italian author (b. 1492)
• 1558 – Julius Caesar Scaliger, Italian physician and scholar (b. 1484)
• 1600 – Ōtani Yoshitsugu, Japanese samurai (b. 1558)

• 1623 – William Wade, English politician and diplomat, Lieutenant of the Tower of London (b. 1546)
• 1662 – Henry Lawes, English composer (b. 1595)
• 1687 – Edmund Waller, English poet and politician (b. 1606)
• 1765 – Giovanni Paolo Panini, Italian painter and architect (b. 1691)
• 1775 – Peyton Randolph, American lawyer and politician, 1st President of the Continental Congress (b. 1721)
• 1777 – Samuel Foote, English actor and playwright (b. 1720)
• 1805 – John Cooke, English captain (b. 1763)^[37]
• 1805 – George Duff, Scottish captain (b. 1764)
• 1805 – Horatio Nelson, 1st Viscount Nelson, English admiral (b. 1758)
• 1821 – Dorothea Ackermann, German actress (b. 1752)
• 1835 – Muthuswami Dikshitar, Indian poet and composer (b. 1775)
• 1861 – Edward Dickinson Baker, American congressman and colonel (b. 1811)
• 1872 – Jacques Babinet, French physicist, mathematician, and astronomer (b. 1794)
• 1873 – Johan Sebastian Welhaven, Norwegian author, poet, and critic (b. 1807)
• 1896 – James Henry Greathead, South African-English engineer (b. 1844)

• 1903 – Jinmaku Kyūgorō, Japanese sumo wrestler, the 12th Yokozuna (b. 1829)
• 1904 – Isabelle Eberhardt, Swiss explorer and journalist (b. 1877)
• 1907 – Jules Chevalier, French priest, founded the Missionaries of the Sacred Heart (b. 1824)
• 1931 – Arthur Schnitzler, Austrian author and playwright (b. 1862)
• 1938 – Dorothy Hale, American actress (b. 1905)
• 1939 – Hendrik Wortman, Dutch civil engineer (b. 1859)^[38]
• 1940 – William G. Conley, American journalist, lawyer, and politician, 18th Governor of West Virginia (b. 1866)
• 1941 – Alexander Greenlaw Hamilton, Australian biologist (b. 1852)
• 1944 – Alois Kayser, German-French missionary (b. 1877)
• 1952 – Hans Merensky, South African geologist and philanthropist (b. 1871)
• 1963 – Józef Franczak, Polish sergeant (b. 1918)
• 1965 – Bill Black, American bass player and bandleader (b. 1926)
• 1969 – Jack Kerouac, American novelist and poet (b. 1922)
• 1969 – Wacław Sierpiński, Polish mathematician and academic (b. 1882)
• 1970 – Li Linsi, Chinese educator and diplomat (b. 1896)
• 1971 – Minnie Evans, American artist (b. 1888)
• 1973 – Nasif Estéfano, Argentinian race car driver (b. 1932)
• 1975 – Charles Reidpath, American runner and general (b. 1887)
• 1977 – Ferit Tüzün, Turkish composer (b. 1929)
• 1978 – Anastas Mikoyan, Armenian-Russian civil servant and politician (b. 1895)
• 1980 – Hans Asperger, Austrian physician and psychologist (b. 1906)
• 1982 – Radka Toneff, Norwegian singer-songwriter (b. 1952)
• 1983 – Joseph P. Lordi, American government official (b. 1919)
• 1984 – François Truffaut, French actor, director, producer, and screenwriter (b. 1932)
• 1985 – Dan White, American assassin and politician (b. 1946)
• 1986 – Lionel Murphy, Australian jurist and politician, 22nd Attorney-General of Australia (b. 1922)
• 1989 – Jean Image, Hungarian-French director, producer, and screenwriter (b. 1910)
• 1990 – Dany Chamoun, Lebanese engineer and politician (b. 1934)
• 1990 – Prabhat Ranjan Sarkar, Indian spiritual guru, philosopher and author (b. 1921)
• 1991 – Lorenc Antoni, Albanian composer, conductor, and musicologist (b. 1909)
• 1992 – Ante Ciliga, Croatian politician, writer and publisher (b. 1898)
• 1992 – Jim Garrison, American lawyer and judge (b. 1921)
• 1993 – Sam Zolotow, American journalist and critic (b. 1899)
• 1995 – Maxene Andrews, American singer (b. 1916)
• 1995 – Jesús Blasco, Spanish author and illustrator (b. 1919)
• 1995 – Nancy Graves, American sculptor and painter (b. 1939)
• 1995 – Shannon Hoon, American singer-songwriter and guitarist (b. 1967)
• 1996 – Georgios Zoitakis, Greek general and politician (b. 1910)
• 1998 – Francis W. Sargent, American soldier and politician, 64th Governor of Massachusetts (b. 1915)
• 1999 – Lars Bo, Danish author and illustrator (b. 1924)
• 1999 – Ahmet Taner Kışlalı, Turkish political scientist, lawyer, and politician (b. 1939)
• 2002 – Edward J. Mortola, American academic and president of Pace University (b. 1917)^[39]
• 2003 – Louise Day Hicks, American politician (b. 1916)
• 2003 – Luis A. Ferré, Puerto Rican engineer and politician, 3rd Governor of Puerto Rico (b. 1904)
• 2003 – Elliott Smith, American singer-songwriter and guitarist (b. 1969)
• 2006 – Sandy West, American singer-songwriter and drummer (b. 1959)
• 2007 – Paul Fox, English singer-songwriter and guitarist (b. 1951)
• 2010 – A. Ayyappan, Indian poet and translator (b. 1949)
• 2011 – Hikmet Bilâ, Turkish journalist and author (b. 1954)
• 2011 – Tone Pavček, Slovenian poet and author (b. 1928)
• 2012 – Yash Chopra, Indian director, producer, and screenwriter (b. 1932)
• 2012 – Antoni Dobrowolski, Polish educator (b. 1904)
• 2012 – Jaroslav Kozlík, Czech volleyball player and educator (b. 1907)
• 2012 – Alf Kumalo, South African photographer and journalist (b. 1930)
• 2012 – George McGovern, American historian, lieutenant, and politician (b. 1922)
• 2013 – Bud Adams, American businessman (b. 1923)
• 2013 – Gianni Ferrio, Italian composer and conductor (b. 1924)
• 2013 – Rune T. Kidde, Danish author, poet, and illustrator (b. 1957)
• 2013 – Colonel Robert Morris, American singer-songwriter and drummer (b. 1954)
• 2013 – Major Owens, American librarian and politician (b. 1936)
• 2013 – Tony Summers, Welsh swimmer (b. 1924)
• 2013 – Oscar Yanes, Venezuelan journalist and author (b. 1927)
• 2014 – Ben Bradlee, American journalist and author (b. 1921)
• 2014 – Nelson Bunker Hunt, American businessman (b. 1926)
• 2014 – Mohammad-Reza Mahdavi Kani, Iranian cleric and politician, Prime Minister of Iran (b. 1931)
• 2014 – Edith Kawelohea McKinzie, Hawaiian genealogist, author, and hula expert (b. 1925)
• 2014 – Gough Whitlam, Australian lieutenant, lawyer, and politician, 21st Prime Minister of Australia (b. 1916)
• 2015 – France Bučar, Slovenian lawyer and politician (b. 1923)
• 2015 – Marty Ingels, American actor (b. 1936)
• 2015 – Norman W. Moore, English conservationist and author (b. 1923)
• 2015 – Sheldon Wolin, American philosopher, theorist, and academic (b. 1922)
• 2020 – Frank Bough, English television presenter (b. 1933)^[40]
• 2021 – Bernard Haitink, Dutch conductor and violinist (b. 1929)^[41]
• 2023 – Bobby Charlton, English footballer and manager (b. 1937)^[42]
• 2023 – Bobi, Portuguese dog (b. 1992)^[43]
• 2023 – Bill Hayden, Australian politician, 21st Governor General of Australia (b. 1933)^[44]
• 2024 – Mimi Hines, Canadian singer and comedian (b. 1933)^[45]

• Armed Forces Day (Honduras)
• Christian feast day:
  • Asterius of Ostia
  • Berthold of Parma
  • Blessed Charles of Austria (Roman Catholic Church)
  • Fintán of Taghmon
  • Hilarion
  • John of Bridlington
  • Laura of Saint Catherine of Siena
  • Leticia
  • Malchus of Syria
  • Peter Yu Tae-chol
  • Severinus of Bordeaux
  • Tuda of Lindisfarne
  • Ursula
  • Viator of Lyons
  • October 21 (Eastern Orthodox liturgics)
• Egyptian Naval Day (Egypt)
• Indian Police Commemoration Day (India)
• National Nurses' Day (Thailand)
• Ndadaye Day (Burundi)
• Overseas Chinese Day (Republic of China)
• Trafalgar Day (the British Empire in the 19th and early 20th century)
• Birth of the Báb (2017) (Baháʼí Faith)

• "On This Day". BBC.
• The New York Times: On This Day
• "Historical Events on October 21". OnThisDay.com.