The First Libyan Civil War was an armed conflict in 2011 in the North African country of Libya which was fought between forces which were loyal to Colonel Muammar Gaddafi and rebel groups that were seeking to oust his government. It erupted with the Libyan Revolution, also known as the 17 February Revolution. The war was preceded by protests in Zawiya on 8 August 2009 and finally ignited by protests in Benghazi beginning on Tuesday, 15 February 2011, which led to clashes with security forces that fired on the crowd. The protests escalated into a rebellion that spread across the country, with the forces opposing Gaddafi establishing an interim governing body, the National Transitional Council.

The United Nations Security Council passed an initial resolution on 26 February, freezing the assets of Gaddafi and his inner circle and restricting their travel, and referred the matter to the International Criminal Court for investigation. In early March, Gaddafi's forces rallied, pushed eastwards and re-took several coastal cities before reaching Benghazi. A further UN resolution authorised member states to establish and enforce a no-fly zone over Libya, and to use "all necessary measures" to prevent attacks on civilians, which turned into a bombing campaign by the forces of NATO against Libyan military installations and vehicles. The Gaddafi government then announced a ceasefire, but fighting and bombing continued. Throughout the conflict, rebels rejected government offers of a ceasefire and efforts by the African Union to end the fighting because the plans set forth did not include the removal of Gaddafi.In August, rebel forces launched an offensive on the government-held coast of Libya, backed by a wide-reaching NATO bombing campaign, taking back territory lost months before and ultimately capturing the capital city of Tripoli, while Gaddafi evaded capture and loyalists engaged in a rearguard campaign. On 16 September 2011, the National Transitional Council was recognised by the United Nations as the legal representative of Libya, replacing the Gaddafi government. Muammar Gaddafi evaded capture until 20 October 2011, when he was captured and killed in Sirte. The National Transitional Council declared "the liberation of Libya" and the official end of the war on 23 October 2011.In the aftermath of the civil war, a low-level insurgency by former Gaddafi loyalists continued. There was various disagreements and strife between local militias and tribes, including fighting on 23 January 2012 in the former Gaddafi stronghold of Bani Walid, leading to an alternative town council being established and later recognized by the National Transitional Council (NTC). A much greater issue had been the role of militias which fought in the civil war and their role in the new Libya. Some refused to disarm, and cooperation with the NTC had been strained, leading to demonstrations against militias and government action to disband such groups or integrate them into the Libyan military. These unresolved issues led directly to a second civil war in Libya.

Muammar Muhammad Abu Minyar al-Gaddafi (c. 1942 – 20 October 2011) was a Libyan revolutionary, politician and political theorist. He was the de facto leader of Libya from 1969 to 2011, first as Revolutionary Chairman of the Libyan Arab Republic from 1969 to 1977 and then as the "Brotherly Leader" of the Great Socialist People's Libyan Arab Jamahiriya from 1977 to 2011. Initially ideologically committed to Arab nationalism and Arab socialism, he later ruled according to his own Third International Theory.

Born near Sirte, Italian Libya, to a poor Bedouin family, Gaddafi became an Arab nationalist while at school in Sabha, later enrolling in the Royal Military Academy, Benghazi. Within the military, he founded a revolutionary group which deposed the Western-backed Senussi monarchy of Idris in a 1969 coup. Having taken power, Gaddafi converted Libya into a republic governed by his Revolutionary Command Council. Ruling by decree, he deported Libya's Italian population and ejected its Western military bases. Strengthening ties to Arab nationalist governments—particularly Gamal Abdel Nasser's Egypt—he unsuccessfully advocated pan-Arab political union. An Islamic modernist, he introduced sharia as the basis for the legal system and promoted "Islamic socialism". He nationalized the oil industry and used the increasing state revenues to bolster the military, fund foreign revolutionaries, and implement social programs emphasizing house-building, healthcare and education projects. In 1973, he initiated a "Popular Revolution" with the formation of Basic People's Congresses, presented as a system of direct democracy, but retained personal control over major decisions. He outlined his Third International Theory that year in The Green Book.

Gaddafi transformed Libya into a new socialist state called a Jamahiriya ("state of the masses") in 1977. He officially adopted a symbolic role in governance but remained head of both the military and the Revolutionary Committees responsible for policing and suppressing dissent. During the 1970s and 1980s, Libya's unsuccessful border conflicts with Egypt and Chad, support for foreign militants, and alleged responsibility for the Lockerbie bombing in Scotland left it increasingly isolated on the world stage. A particularly hostile relationship developed with the United States, United Kingdom and Israel, resulting in the 1986 U.S. bombing of Libya and United Nations–imposed economic sanctions. From 1999, Gaddafi shunned pan-Arabism and encouraged rapprochement with Western nations and pan-Africanism; he was Chairperson of the African Union from 2009 to 2010. Amid the 2011 Arab Spring, protests against widespread corruption and unemployment broke out in Eastern Libya. The situation descended into civil war, in which NATO intervened militarily on the side of the anti-Gaddafist National Transitional Council (NTC). The government was overthrown and Gaddafi retreated to Sirte, only to be captured and killed by NTC militants.

A highly divisive figure, Gaddafi dominated Libya's politics for four decades and was the subject of a pervasive cult of personality. He was decorated with various awards and praised for his anti-imperialist stance, support for Arab—and then African—unity, as well as for significant improvements that his government brought to the Libyan people's quality of life. Conversely, many Libyans strongly opposed Gaddafi's social and economic reforms; he was posthumously accused of sexual abuse. He was condemned by many as a dictator whose authoritarian administration systematically violated human rights and financed global terrorism.