- December 2 – 22-year-old Robert B. Ennis, Jr. stabs 20-year-old Jamie Friend to death on Popes Head Road in Clifton in an incident of road rage.
- December 2 – 77-year-old Margaret Masnik is struck and killed by 23-year-old Pedro Carranza as she crosses Leesburg Pike at South Jefferson Street in Bailey's Crossroads. Carranza flees the scene, and Masnik is taken to Alexandria Hospital, where she is pronounced dead.
- December 4 – 19-year-old Louis V. Arai is convicted of first-degree murder, robbery, and use of a firearm for shooting 7-Eleven clerk Mohammad Jamal Tafwiz in a penny-ante robbery in the Lincolnia area of Alexandria on September 25 which netted Arai a total of eight dollars.
- Davis, Patricia. "Manassas Park School Grieves for Ex-Athlete ;Man Slain After Roadside Altercation." The Washington Post (pre-1997 Fulltext): 0. Dec 04 1990. ProQuest. Web. 2 Jan. 2014.
- Brown, DeNeen L. "Clifton Man Convicted in Stabbing." The Washington Post (1974-Current file): 1. Mar 30 1991. ProQuest. Web. 2 Jan. 2014.
- "Woman Killed in Hit-and-Run Accident." The Washington Post (pre-1997 Fulltext): c07. Dec 04 1990. ProQuest. Web. 29 Jan. 2018.
- Associated Press. "VA. DRIVER'S LICENSE SCAM REVEALED AT DMV BRANCH." Roanoke Times, The (VA), 27 Mar. 1991, EVENING, VIRGINIA, p. B6. NewsBank. Accessed 29 Jan. 2018.
- Brown, DeNeen L. "Man Convicted in Slaying of Afghan War Survivor." The Washington Post (1974-Current file): 1. Dec 05 1990. ProQuest. Web. 22 Sep. 2014.
|Fairfax County by Year: 1990|
|November 1990||·||December||·||January 1991|