Drone warfare is a form of warfare using military drones or military robots. The robots may be remote controlled by a pilot or have varying levels of autonomy during their mission. Types of robots include unmanned combat aerial vehicles (UCAV) or weaponized commercial unmanned aerial vehicles (UAV), unmanned surface vehicles (USV) or unmanned underwater vehicles (UUV), and unmanned ground vehicles (UGV). UAVs, UGVs, USVs and UUVs are variously used for reconnaissance, kamikaze missions, bomb disposal, transporting cargo and medical evacuation or may serve an anti-air, anti-armor or anti-personnel role. China, France, Greece, India, Iran, Iraq, Israel, Italy, Pakistan, Poland, Russia, South Korea, Turkey, the United States, the United Kingdom and Ukraine are known to have manufactured operational UCAVs as of 2019.

Drones can be used for electronic warfare, explosive ordnance disposal, training and augmenting logistics but are most commonly utilized for intelligence, surveillance, target acquisition, and reconnaissance (ISTAR), facilitating direct attacks on target as part of a kill chain or manned-unmanned teaming. Aerial drone attacks can be conducted via purpose-built UCAVs deploying ordnance during a drone strike or by weaponized commercial UAVs that drop munitions or crash into a target. Heavy-lift drones may also be used to airlift supplies or transport wounded personnel across a battlefield. Smaller drones, such as SUAVs and MAVs are man-portable and can be deployed for low-altitude, short-range support operations. Larger drones can serve a "mothership" role by deploying smaller, sub-drones or by being equipped with electronic warfare features such as a signal repeater. Multiple drones may operate and attack simultaneously in a drone swarm and autonomous drones, such as LAWs, utilize military AI.

The early years of the 21st century saw most drone strikes being conducted by the US military using air-to-surface missiles against ground targets within countries such as Afghanistan, Libya, Pakistan, Somalia, Syria, and Yemen during the war on terror. Drone warfare evolved and proliferated quickly in the 2010s and 2020s, with countries such as Azerbaijan, China, Iran, Russia, Turkey and Ukraine utilizing drones with increased ubiquity. Militant groups, such as the Islamic State and Houthis, and organized crime groups such as Mexican cartels likewise used drones for attacks against adversaries and for logistical purposes. Since 2022, drone warfare has been extensively used in the Russian invasion of Ukraine by both sides, including long range fixed-wing drones, and short range multirotor FPV drones. Scholars have described the conflict as the first "drone war", due to the large scale and high intensity of attacks, and agree on the major role drone warfare has in modern conventional warfare.

A commercial UCAV is any commercially-produced UAV that is modified to carry such weapons as guided bombs, cluster bombs, incendiary devices, air-to-surface missiles, air-to-air missiles, anti-tank guided missiles or other types of precision-guided munitions, autocannons and machine guns. These weaponized civilian drones may proceed to fire munition or a missile, drop explosives and crash into or detonate above vulnerable targets. Payloads could include explosives such as hand grenades, mortar shells and IEDs or other dangerous materials such as shrapnel, chemical, radiological or biological hazards. These relatively cheap drones are also used for non-attack roles. Multirotor FPV drones have been used extensively by both armies for aerial reconnaissance and artillery spotting in the Russo-Ukraine War.

Anti-UAV systems are being developed by states to counter the threat posed by commercial UCAVs. According to James Rogers, an academic who studies drone warfare, "There is a big debate out there at the moment about what the best way is to counter these small UAVs, whether they are used by hobbyists causing a bit of a nuisance or in a more sinister manner by a terrorist actor."

Estimates for the total number of people killed in U.S. drone strikes in Pakistan range from 2,000 to 3,500 militants killed and 158 to 965 civilians killed. 81 insurgent leaders in Pakistan have been killed. Drone strikes in Yemen are estimated to have killed 846–1,758 militants and 116–225 civilians. 57 Al-Qaeda in the Arabian Peninsula leaders are confirmed to have been killed.

In August 2018, Al Jazeera reported that a Saudi Arabian-led coalition combating Houthi rebels in Yemen had secured secret deals with al-Qaeda in Yemen and recruited hundreds of that group's fighters: "... Key figures in the deal-making said the United States was aware of the arrangements and held off on drone attacks against the armed group, which was created by Osama bin Laden in 1988."

After US president Donald Trump had increased drone strikes by over 400%, his successor Joe Biden reversed course. Under Biden, drone strikes reportedly decreased. A Biden administration drone strike in Kabul, Afghanistan in August 2021 killed 10 civilians, including seven children. Later, a drone strike killed Al-Qaeda leader Ayman al-Zawahiri.