- Children's Day (Singapore)
- Earliest day on which World Habitat Day can fall, while October 7 is the latest; celebrated on the first Monday of October. (International)
- Independence Day, celebrates the independence of Cyprus from United Kingdom in 1960.
- Independence Day, celebrates the independence of Nigeria from United Kingdom in 1960.
- Independence Day, celebrates the independence of Palau from the UN Trust Territory status in 1994.
- Independence Day, celebrates the independence of Tuvalu from United Kingdom in 1978.
- International Day of Older Persons (International)
- Moving Day (New York City from the mid-19th century to c.1945)
- National Day of the People's Republic of China (China)
- World Vegetarian Day (from North American Vegetarian Society)
October 02:
- Gandhi's birthday-related observances:
- Independence Day, celebrates the independence of Guinea from France in 1958.
October 03:
- German Unity Day (Germany)
- National Day, celebrates the independence of Iraq from the United Kingdom in 1932.
- National Foundation Day or Gaecheonjeol (South Korea)
October 04:
- Cinnamon Roll Day or kanelbullens dag (Sweden) http://hallosushant.blogspot.com/
- Independence Day, celebrates the independence of Lesotho from Great Britain in 1966.
- The beginning of World Space Week (International)
- World Animal Day (International)
October 05:
October 06:
- German-American Day (United States)
- Armed Forces Day, commemorates the October War in 1973. (Egypt)
October 08:
- Independence Day, celebrate the official separation of Croatia from Yugoslavia in 1991.
- Navy Day (Peru)
- Discoverer's Day (Hawaii)
October 09:
- Hangul Day (South Korea)
- Independence Day, celebrates the independence of Uganda from United Kingdom in 1962.
- Independence of Guayaquil from Spain in 1820 (Guayaquil)
- Leif Erikson Day (United States, Iceland and Norway)
- National Day of Commemorating the Holocaust (Romania)
October 10:
- Double Ten Day (雙十國慶), celebrate outbreak of the Wuchang Insurgence that led to founding of the Republic of China or Taiwan in 1911. http://hallosushant.blogspot.com/
- Fiji Day, celebrate the independence of Fiji from United Kingdom in 1970.
- National Health-Sports Day until 2000; since made a moveable feast on the second Monday in October. (Japan)
- Party Foundation Day, the foundation of the Workers' Party of Korea (North Korea)
- The Day of Finnish literature, birthday of the National writer Aleksis Kivi. (Finland)
- World Mental Health Day (International)
October 11:
- National Coming Out Day (Multinational, including United Kingdom, Switzerland, and United States among others.)
- Old Michelmas Day (Celtic)
- Revolution Day (Republic of Macedonia)
October 12:
- Freethought Day (United States)
- Independence Day, celebrates the independence of Equatorial Guinea from Spain in 1968.
- Mother's Day (Malawi)
- National Coming Out Day (United Kingdom)
- Children's Day or Feast of Our Lady of Aparecida (Brazil)
Discovery of America by Columbus-related observances:
- Día de la Hispanidad or Fiesta Nacional de España (Spain)
- Día de la Raza, "Day of the Race" (Latin America)
- Día de la Resistencia Indígena, "Day of Indigenous Resistance" (Venezuela)
- Día de las Américas, "Day of the Americas" (Uruguay)
- Día de las Culturas, "Day of the Cultures" (Costa Rica)
- Discovery Day (the Bahamas)
October 13:National Police Day (Thailand)
October 14:
- National Education Day, formerly Teachers' Day (Poland)
- Nyerere Day (Tanzania)
- World Standards Day (International)
October 15:
- Global Handwashing Day (International observance|International)
- Pregnancy and Infant Loss Remembrance Day (Canada and the United States)
- Teachers' Day (Brazil)
- The Equirria or October equus, sacrifice of a horse to Mars. (Roman Empire)
- White Cane Safety Day (United States)
October 16:
- Day of Pope John Paul II (Poland)
- World Food Day (International)
- Boss's Day (United States and Canada)
October 17:
- Dessalines Day (Haiti)
- International Day for the Eradication of Poverty (International)
- Loyalty Day (Argentina)
- National Edge Day (Straight edge movement)
October 18:Alaska Day (Alaska)
October 19:
- Constitution Day, in honor of the country's independence (self-governing in free association with New Zealand) in 1974. (Niue) http://hallosushant.blogspot.com/
- Independence Day of State of Piauí (Brazil)
- Mother Teresa Day (Albania)
October 20:
- Kenyatta Day (Kenya)
- Revolution Day, one of the two Patriotic Days (Guatemala)
October 21:
- International Day of the Nacho (Mexico and USA)
- National Nurses' Day (Thailand)
- Overseas Chinese Day (Republic of China)
- Trafalgar Day (the British Empire in the 19th and early 20th Century)
- Apple Day (United Kingdom)
October 22:
October 23:
- Chulalongkorn Day (Thailand)
- Day of the Macedonian Revolutionary Struggle (Republic of Macedonia)
- Mole Day (Chemists)
- National Day (Hungary)
October 24:
- Independence Day, celebrate the independence of (Zambia) from United Kingdom in 1964.
- Maladay (Discordianism) http://hallosushant.blogspot.com/
- United Nations Day, the anniversary of the 1945 Charter of the United Nations (International)
- World Development Information Day (International)
October 25:
- Republic Day (Kazakhstan)
- Retrocession Day (Taiwan)
- Thanksgiving Day (Grenada)
- Armed Forces Day (Romania)
October 26:
- National Day, celebrates the anniversary of the Declaration of Neutrality in 1955. (Austria)
- The first day of Ludi Victoriae Sullanae, celebrated until November 1. (Roman Empire)
- Angam Day (Nauru)
October 27:
- Independence Day, celebrates the independence of Saint Vincent and the Grenadines from Britain in 1979. http://hallosushant.blogspot.com/
- Independence Day, celebrates the independence of Turkmenistan from USSR in 1991.
- Navy Day, first organized to be on this day. (United States)
October 28:
- Day of the Establishment of an Independent Czecho-Slovak State, celebrates the independence of Czechoslovakia from Austria-Hungary in 1918.(Slovakia)
- Independence Day, celebrates the independence of Czechoslovakia from Austria-Hungary in 1918.
- Ochi Day (Greece, Cyprus and the Greek communities)
- Prefectural Earthquake Disaster Prevention Day (Gifu Prefecture)
October 29:
- Coronation Day (Cambodia)
- Republic Day or Cumhuriyet Bayramı (Turkey)
October 30:
- Day of Remembrance of the Victims of Political Repressions (former Soviet republics, except Ukraine)
- Mischief Night (United States)
October 31:
- Halloween
- Reformation Day (Slovenia and Protestant Church)
- Samhain in the northern hemisphere, Beltane in the southern hemisphere; begins on sunset of October 31 (Gaels, Welsh people and Neopagans)
- Allantide (Cornwall, United Kingdom)
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