- October 1 – 49-year-old Alfredo R. Prieto is executed by lethal injection at the Greenville Correctional Center in Jarratt for the murders of Rachael A. Raver and Warren H. Fulton, III in Reston in 1988.
- October 4 – 34-year-old Jose Anibar Cisneros is fatally shot by Charles W. Kibler in the Groveton area of Alexandria.
- October 21 – 72-year-old Silvia Raquel Corella Erazo is struck and mortally injured by a 30-year-old Sterling-area man driving a 2005 Honda Accord as she attempts to cross Wiehle Avenue near Chestnut Grove Square in Reston. Corella is taken to the Reston Hospital Center, where she dies.
- October 30 – W. T. Woodson High School Chemistry teacher Susan Sharaf burns herself and five students, two of them seriously, while performing a demonstration for the class. Three of the injured students are taken to Inova Fairfax Hospital, while the two most critically injured victims, Sonya Garvis and Nolan Ward, are flown to MedStar Washington Hospital Center in Washington, D.C. The fire also causes the school's evacuation, and is estimated to have caused $7500 in damage.
- Jackman, Tom. "Triple Murderer Alfredo Prieto Is Executed in Virginia." Washington Post. The Washington Post, 1 Oct. 2015. Web. 02 Mar. 2016.
- FCPD Public Affairs Bureau. "UPDATE - Death Investigated as a Homicide." Fairfax County Police Department News. Fairfax County Police Department, 05 Oct. 2015. Web. 17 Feb. 2016.
- Hedgpeth, Dana. "Man Found Fatally Shot in Fairfax on Sunday Is Identified." Washington Post. The Washington Post, 5 Oct. 2015. Web. 29 Feb. 2016.
- FCPD Public Affairs Bureau. "Update-Arrest Made in Homicide." Fairfax County Police Department News. Fairfax County Police Department, 28 July 2016. Web. 30 Sept. 2016.
- FCPD Public Affairs Bureau. "Fatal Pedestrian Crash in Reston." Fairfax County Police Department News. Fairfax County Police Department, 21 Oct. 2015. Web. 22 Jan. 2017.
- Leshan, Bruce, and Nikki Burdine. "5 Students, 1 Teacher Injured in Fire at Woodson High School." WUSA9. WUSA9, 30 Oct. 2015. Web. 29 Feb. 2016.
- Ramirez, Stephanie. "Student Injured in Woodson HS Fire Needs Surgery, 'will Recover'"WUSA9. WUSA9, 31 Oct. 2015. Web. 29 Feb. 2016.
- Reyes, Jeannette, and Suzanne Kennedy. "Woodson High School Students Head Back to School after Fire." WJLA. Sinclair Broadcast Group, Inc., 4 Nov. 2015. Web. 29 Feb. 2016.
|Fairfax County by Year: 2015|
|September 2015||·||October||·||November 2015|