1985-December

• December 1
  • Ibero-American States Organization for Education, Science and Culture (Organización de Estados Iberoamericanos para la Educación la Ciencia y la Cultura) (OEI) created.
  • The Ford Taurus and Mercury Sable are released for sale to the public.
• December 8 – South Asian Association for Regional Cooperation (SAARC) established.
• December 12 – Arrow Air Flight 1285, a Douglas DC-8, crashes after takeoff in Gander, Newfoundland, killing 256, 248 of whom were U.S. servicemen returning to Fort Campbell, Kentucky from overseeing a peacekeeping force in Sinai.
• December 16 – In New York City, Mafia bosses Paul Castellano and Thomas Bilotti are shot dead in front of Spark's Steak House, making hit organizer John Gotti the leader of the powerful Gambino organized crime family.
• December 24 – Right wing extremist David Lewis Rice murders civil rights attorney Charles Goldmark as well as Goldmark's wife and 2 children in Seattle. Rice suspected the family of being Jewish and Communist and claimed his dedication to the Christian Identity movement drove him to the crime.
• December 27
  • Rome and Vienna airport attacks: Abu Nidal terrorists open fire in the airports of Rome and Vienna, leaving 18 dead and 120 injured.
  • American naturalist Dian Fossey is found murdered in Rwanda.
• December 31 – The last issue of The Columbus Citizen-Journal is circulated.