| 121381 | October 23 | Death | 2009 – Lou Jacobi, Canadian-American actor (b. 1913) |
| 121382 | October 23 | Death | 2010 – Fran Crippen, American swimmer (b. 1984) |
| 121383 | October 23 | Death | 2010 – Stanley Tanger, American businessman and philanthropist, founded the Tanger Factory Outlet Centers (b. 1923) |
| 121384 | October 23 | Death | 2011 – Herbert A. Hauptman, American chemist and mathematician, Nobel Prize laureate (b. 1917) |
| 121385 | October 23 | Death | 2011 – John McCarthy, American computer scientist and academic, developed the Lisp programming language (b. 1927) |
| 121386 | October 23 | Death | 2011 – Marco Simoncelli, Italian motorcycle racer (b. 1987) |
| 121387 | October 23 | Death | 2012 – William Joel Blass, American lawyer and politician (b. 1917) |
| 121388 | October 23 | Death | 2012 – Wilhelm Brasse, Polish photographer (b. 1917) |
| 121389 | October 23 | Death | 2012 – Roland de la Poype, French soldier and pilot (b. 1920) |
| 121390 | October 23 | Death | 2012 – Sunil Gangopadhyay, Indian author and poet (b. 1934) |
| 121391 | October 23 | Death | 2012 – Michael Marra, Scottish singer-songwriter (b. 1952) |
| 121392 | October 23 | Death | 2013 – Wes Bialosuknia, American basketball player (b. 1945) |
| 121393 | October 23 | Death | 2013 – Anthony Caro, English sculptor and academic (b. 1924) |
| 121394 | October 23 | Death | 2013 – Niall Donohue, Irish hurler (b. 1990) |
| 121395 | October 23 | Death | 2013 – Gypie Mayo, English guitarist and songwriter (Dr. Feelgood and The Yardbirds) (b. 1951) |
| 121396 | October 23 | Death | 2013 – Bill Mazer, Ukrainian-American journalist and sportscaster (b. 1920) |
| 121397 | October 23 | Death | 2014 – Ghulam Azam, Bangladeshi politician (b. 1922) |
| 121398 | October 23 | Death | 2014 – John Bramlett, American football player (b. 1941) |
| 121399 | October 23 | Death | 2014 – Bernard Mayes, English-American journalist and academic (b. 1929) |
| 121400 | October 23 | Death | 2014 – Joan Quigley, American astrologer and author (b. 1927) |
| 121401 | October 23 | Death | 2014 – Tullio Regge, Italian physicist and academic (b. 1931) |
| 121402 | October 23 | Death | 2014 – Alvin Stardust, English singer and actor (b. 1942) |
| 121403 | October 23 | Death | 2015 |
| 121404 | October 23 | Death | 2015 – Leon Bibb, American-Canadian singer (b. 1922) |
| 121405 | October 23 | Death | 2015 – Roger De Clerck, Belgian businessman (b. 1924) |
| 121406 | October 23 | Death | 2015 – Jim Roberts, Canadian-American ice hockey player and coach (b. 1940) |
| 121407 | October 23 | Death | 2015 – Fred Sands, American businessman and philanthropist, co-founded the Museum of Contemporary Art (b. 1938) |
| 121408 | October 23 | Holiday and observance | Christian feast day:Anicius Manlius Severinus BoethiusJames the Just (Lutheran/Episcopal Church)Giovanni da CapistranoIgnatios of ConstantinopleSeverin of CologneOctober 23 (Eastern Orthodox liturgics) |
| 121409 | October 23 | Holiday and observance | Chulalongkorn Day (Thailand) |
| 121410 | October 23 | Holiday and observance | Day of the Macedonian Revolutionary Struggle (Republic of Macedonia) |