Friendly fire incidents are caused by miscommunication among military and friendly forces on the same side. The two most common types stem from errors of targeting and errors of identification.
- "Fratricide is the employment of friendly weapons and munitions with the intent to kill the enemy or destroy his equipment, or facilities, which result in unforeseen and unintentional death or injury to friendly personnel."
In the confusion of battle, it is easy to shoot one's own comrades in arms, accidentally. Nonetheless, U.S. troops are required to exercise care and can be prosecuted if their negligence results in death.
Friendly fire losses are common in wars, as exemplified by friendly fire attacks on 53 US naval vessels during World War II that killed 186 sailors and wounded 438. These incidents mostly occurred in large-scale amphibious or aircraft carrier operations late in the war.
- In May 2, 1863, Confederate General Stonewall Jackson was wounded by fellow Confederate soldiers and died 8 days later in May 10 during the Battle of Chancellorsville.
- August 14, 1944: During Operation Tractable in north of Falaise, Normandy, France, RAF heavy bombers bombed Canadian and Polish troops in error, causing about 490 casualties including 112 dead. The bombings also wiped out 265 Allied vehicles, 30 field guns and two tanks.
- November 6, 1956: During a raid to capture Port Said, Egypt, a British Royal Navy carrier-borne aircraft attacked the British Army of No. 45 Commando Royal Marines and HQ, causing heavy casualties.
- July 3, 1950: Eight Australian P-51s of the No. 77 Squadron RAAF destroyed a train carrying thousands of American and South Korean soldier were mistaken for a North Korean convoy in the main highway between Suwon and P'yongtaek, resulting more than 700-1000 casualties.
- September 23, 1950: During a Battle for 'Hill 282', three U.S. Air Force P-51 aircraft mistakenly dropped napalm bombs along with machine gun fire on a hill occupied by the British Army of 1st Battalion, Argyll and Sutherland Highlanders, killing 17 and wounded 76.
- August 11, 1966: The U.S. Coast Guard cutter Point Welcome (WPB-82329) was on a routine patrol off the coast of Vietnam when they were attacked by USAF warplanes, killing two U.S. sailors and wounded five others. An inquiry blamed the incident on a lack of coordination between the air force and navy on rules of engagement identification procedures.
Falklands War 1982
- Companies A and C of the 3rd Battalion, Parachute Regiment, British Army engaged each other in an hour-long firefight in the Falkland Islands involving heavy weapons and artillery strikes, resulting eight casualties.
- British Patrol units of 45 Commando Royal Marines fired on a British mortar section who were mistaken for an Argentinian unit in the Falkland Islands, killing five Royal Marines.
- June 2, 1982: British Special Boat Service(SBS) Commando, Sergeant Ian Hunt, was killed in a firefight with British Special Air Service(SAS) Commandos in the Falkland Islands.
- June 6, 1982: A British Royal Navy HMS Cardiff (D108) ship shot down a British Gazelle helicopter in the Falkland Islands. Four British soldiers on board were killed.
- June 11, 1982: A British Royal Navy HMS Avenger (F185) ship fired a 4.5 inch explosive shell into a house while shelling a port in Stanley, Falkland Islands, killing three British women and several others were wounded. They are the only British civilian casualties of the war.
First Gulf War
- February 26, 1991: Two U.S. Air Force A-10 Thunderbolt II aircraft during Operation Desert Storm attacked British armoured personnel carriers with Maverick missiles, killing nine British soldiers and wounded 11 more.
- February 26, 1991: A British officer was wounded when his Warrior vehicle was attacked by a Challenger 1 tank of the Scots Dragoon Guards.
- February 27, 1991: Two British soldiers from 10 Air Defence Battery, Royal Artillery were injured when two Spartan armoured vehicles from which they had dismounted were engaged by Challenger 1 tanks from 14/20 Hussars with thermal sights beyond the range of unaided visibility (about 1500 m). The rearmost vehicle was hit and burst into flames. The other vehicle was also damaged in the ensuing fire.
War in Afghanistan
- April 18, 2002: In the Tarnak Farm incident, four Canadian soldiers were killed and eight others injured when U.S. Air National Guard Major Harry Schmidt piloting his F-16 fighter aircraft dropped a laser-guided 500 lb (230 kg) bomb on the Princess Patricia's Canadian Light Infantry regiment which was conducting a night firing exercise near Kandahar, Afghanistan.
- April 22, 2004: American Ranger Pat Tillman, a former famous football player, was shot and killed by American fire in Afghanistan.
- March 29, 2006: American soldier, Sergeant John T. Stone, was killed and another wounded, Canadian soldier, Private Robert Costall, was killed and three more wounded, and another Afghan soldier was wounded in which an American Special Force soldier manning a Humvee-mounted M240 machine-gun fired on their positions while defending a coalition outpost against the Taliban assault in Helmand Province, Afghanistan.
- August 9, 2006: Master Corporal Jeffrey Scott Walsh, from 2nd Battalion of the Princess Patricia's Canadian Light Infantry, was conducting routine operations along Highway One near the Zhari district centre, about 20 kilometres west of Kandahar, Afghanistan, when he was shot and killed by a fellow Canadian soldier.
- January 15, 2007: Lance Corporal Matthew Ford, from Zulu Company of 45 Commando Royal Marines, was killed by a bullet round fired from a British Royal Marine machine-gunner who mistook Ford and his unit for the Taliban during an offensive operation to the south of Garmsir in southern Helmand, Afghanistan.
- August 23, 2007: A USAF F-15 aircraft called in to support the British forces dropped a bomb on these forces due to the incorrect coordinates given to a U.S. pilot by the British Forward Air Controller, killing three privates of 1st Battalion, Royal Anglian Regiment with two others wounded. The British Forward Air Controller is currently facing manslaughter charges.
- September 26, 2007: Two Danish soldiers from the Royal Life Guards were killed by British Javelin anti-tank missiles during combat operations in Helmand Province, Afghanistan.
- July 9, 2008: A British Army Apache helicopter open fire on British soldiers from the 2nd Battalion, The Parachute Regiment, wounding nine in Upper Gereshk Valley, Helmand Province, Afghanistan.
- December 20, 2009: A British Military Police officer was shot and killed by a British Army sniper while on patrol. No charges were brought against a British army sniper who killed a British military police officer.
- December 5, 2010: A Kiwi-born Private John 'Jack' Howard of 3rd Battalion, the Parachute Regiment, serving in the British military was killed by a low-cannon fire from a USAF F-18 aircraft in Nad 'Ali district of Helmand Province, Afghanistan, during a firefight with the Taliban in a bad weather.
- March 24, 2003: Sergeant Steven Roberts, a tank commander with the 2nd Royal Tank Regiment, was killed when a fellow British soldier manning a tank-mounted machine gun mistakenly fired at him while trying to shoot a wielding Iraqi protester near Basra, Iraq.
- March 25, 2003: Two British soldiers, Corporal Stephen John Allbutt and Trooper David Jeffrey Clarke, were killed when their Challenger 2 tank was hit by a round fired on from another British tank in southern Iraq.
- March 30, 2003: British Royal Marine Christopher Maddison was killed when his river patrol boat was hit by missiles fired upon by British Royal Engineers who mistook him for an enemy vessel in Al-Faw Peninsula, Iraq.
- April 2, 2003: A U.S. F/A-18 fighter aircraft was shot down by a U.S. Patriot missile in west of Karbala, Iraq, killing U.S. Navy pilot Lieutenant Nathan Dennis White of VFA-195, Carrier Air Wing Five.
- Garrison, Webb. Friendly Fire in the Civil War: More than 100 True Stories of Comrade Killing Comrade. (Nashville: Rutledge Hill, 1999). 229 pp.
- Gauker, Eleanor D. and Blood, Christopher G. "Friendly Fire Incidents During World War Ii Naval Operations." Naval War College Review 1995 48(1): 115-122. 0028-1484
- Friendly Fire incidents in Desert Storm
- Friendly Fire Incidents
- We Brits invented ‘friendly fire’
- UK military deaths in Iraq
- (Eliminating Fratricide In Ground Combat), Defense Update
- It's this combination of increasingly lethal firepower, fluid battlefields, complex communications, and the notorious "fog of war" that can add up to friendly fire losses. (Brad Knickerbocker), The Christian Science Monitor
- Military commanders have occasionally leveled charges of involuntary manslaughter in high-profile friendly-fire cases, such as one in 2002 when Maj. Harry Schmidt, an Illinois National Guard pilot, mistakenly bombed Canadian troops in Afghanistan. But ... there is no uniform, openly published military case law about when friendly-fire cases cross the line from accident to crime . . . " 
- Gauker and Blood, (1995)
- Bickers, Air War Normandy, p.122 and p.251,Ian Gooderson, Air Power at the Battlefront, Allied Close Air Support in Europe 1943-45 (London, Portland, OR: Frank Cass, 1998)
- The Suez Crisis of 1956
- Official History of Australia in the Korean War, Volume II: Combat Operations Page 305.
- "Friendly Fire on Hill 282"
- William R. Wells, II, "Friendly Target," Naval History 1998 12(3): 33-36. 1042-1920
- Special Air Service (SAS) - The Falklands Conflict/
- Part 41. 3 COMMANDO REACHES STANLEY DEFENCES
- Falkland Wars
- Remembering the victims of the Falklands war
- U.S. Friendly fire pilot reported being fired upon
- Officials to Investigate Incident that Killed U.S., Canadian Troops
- Canadian soldier died by friendly fire: U.S. report
- Accidentally shot, soldier buried in Regina
- Soldier's lawyer wants charges dropped
- Royal marine died in friendly fire during battle with Taliban
- British soldier faces manslaughter charges over Afghanistan 'friendly fire' deaths
- Danish soldiers killed by British friendly fire
- Nine British soldiers injured in 'friendly fire
- Military police officer killed by British 'friendly fire' in Afghanistan
- Sniper escapes prosecution over friendly fire death
- Soldier killed by US friendly fire was a New Zealander in British army
- Bureaucratic delay resulted in soldier's death The Guardian
- UK soldiers killed by 'friendly fire'
- Failings' behind death of marine
- Widow of U.S. Naval Pilot Shot Down by Friendly Fire in Iraq Sues Raytheon Company for Wrongful Death