thumb|right|240px|A political map of [[Sudan]]

Operation Lifeline Sudan (OLS) was a consortium of United Nations agencies (mainly UNICEF and the World Food Programme) and approximately 35 non-governmental organizations operating in southern Sudan to provide humanitarian assistance throughout war-torn and drought-afflicted regions in the South. Operation Lifeline Sudan was established in April 1989 in response to a devastating war-induced famine and other humanitarian consequences of the Second Sudanese Civil War between the Sudanese government and South Sudanese rebels. It was the result of negotiations between the UN, the Government of Sudan and the Sudan People's Liberation Movement/Army (SPLM/A) to deliver humanitarian assistance to all civilians in need, regardless of their location or political affiliation. Lokichogio was the primary forward operations hub for OLS.

This mission lasted until the conclusion of the Second Sudanese Civil War with the signing of the 2005 Comprehensive Peace Agreement. An additional 5 million people became internally-displaced individuals while over 500,000 more fled to neighboring countries as refugees. The increasing spillover from the conflict onto other countries in the form of refugees as well as increasing media coverage of the growing crisis led to a call for organizations like the UN to intervene and provide humanitarian assistance. One of the first tests of this neutral model came with the attempted concurrent distribution of aid to the SPLM/A held city of Yirol and the government held city of Wau. Amidst this rejection by both parties, international actors lost interest and viewed the operation as a publicity stunt that failed to consider sovereignty. Consequently, a 1989 conference dedicated to relief operations was held in Khartoum, leading to an agreement that Operation Lifeline Sudan would a UN "umbrella organization" that would grant both diplomatic legitimacy and operational capacity to humanitarian aid distributed to both sides of the Second Sudanese Civil War. Central to this agreement was the principle that "corridors of tranquility" would allow for the safe transportation and impartial distribution of essential food aid through either the air or through roads.

  1. All relevant parties would respect and not hinder the delivery or transportation of humanitarian aid to populations in crisis. Conversely, the Southern sector of Operation Lifeline Sudan was defined by its cooperation with the Sudan People's Liberation Movement/Army. Because the SPLM/A and its regional allies were non-state actors, OLS was not constrained by international norms surrounding sovereignty which dictated that interventions like it would usually operate in deference to the domestic government.