Guerrilla warfare is a form of unconventional warfare in which small groups of irregular military, such as rebels, partisans, paramilitary personnel or armed civilians including recruited children, use ambushes, sabotage, terrorism, raids, petty warfare or hit-and-run tactics in a rebellion, in a violent conflict, in a war or in a civil war to fight against regular military, police or rival insurgent forces.

Unconventional warfare (UW) is broadly defined as "military and quasi-military operations other than conventional warfare" and may use covert forces or actions such as subversion, sabotage, espionage, biowarfare, sanctions, propaganda or guerrilla warfare. This is typically done to avoid escalation into conventional warfare as well as international conventions.