The Bougainville civil war is a classic case of a sovereignty-based conflict. Although it started as a protest against a mining operation in Central Bougainville, the mine's adverse social and environmental impacts, the violence employed to suppress the protests and the massive violation of human rights against the people of Bougainville transformed the conflict into a secessionist war. Bougainville eventually demanded independence from PNG based on the principle of the right to self-determination. The civil war formally ended on August 30, 2001 with the signing of the Bougainville Peace Agreement (BPA). The resolution of the Bougainville conflict is considered a success story in the resolution of sovereignty-based conflicts. Proponents of the earned sovereignty approach often cite it as proof of its effectiveness in resolving secessionist conflicts. The earned sovereignty approach is based on three core elements of shared sovereignty, institution building and determination of final status. This dissertation discusses how these three core elements have been incorporated into the provisions of the BPA - i.e. shared sovereignty through autonomous arrangements; institution building through the formation of the autonomous regional government; determination of the final status through a process that includes and starts with a mandated non-binding referendum. It then evaluates whether the approach has indeed been effective not only in ending the war but in ensuring a long-lasting peaceful resolution to the sovereignty-based conflict between PNG and Bougainville. In the course of this study, the dissertation looks into the basis in international and domestic law of Bougainville’s right to self-determination and its effects on PNG’s right to sovereignty and territorial integrity. There is no doubt that the BPA clearly acknowledges the right of the people of Bougainville to self-determination, which can be exercised through internal or external self-determination. Internal self-determination is often through the grant of autonomy to the sub-state entity, which was the case in Bougainville. Although not explicitly stated in the document, this right was unequivocally recognized by the BPA and the various legal documents enacted pursuant to the peace agreement. Together, they grant autonomous status to the region of Bougainville via the formation of a regional government. Through an Organic Law, several governmental functions and powers were progressively devolved to the Autonomous Bougainville Government (ABG), which was created following the signing of the peace agreement. The dissertation, however, noted that the implementation of the autonomy arrangements has been fraught with challenges and the goal of institution building has not been fully achieved. The BPA did not guarantee Bougainville's right to external self-determination. Often associated with secession, it is frowned upon by the international community. It is thus difficult to justify under international law, which favors the right of sovereignty and respect of the principle of territorial integrity. International law principles further state that secession is only possible in extreme circumstances – i.e. when there is massive violation of human rights and effective denial of the right to participate in the government. As noted above, this is not the case in Bougainville since its right to internal self-determination has been recognized by PNG. Secession is also only acceptable when the parent state gives its consent to the seceding sub-state entity. Non-consensual secession often results in non-recognition by the international community of the seceding sub-state entity. It does not mean, however, that Bougainville can no longer pursue its aspiration to become independent. The autonomy arrangements are but an interim measure preparatory to the determination of its final political status. Consistent with the earned sovereignty approach, the decision on the political status of Bougainville would commence with the conduct of a non-binding referendum within 10-15 years after the establishment of the autonomous government. The BPA stipulates that the option of independence as one of the choices to be presented to the people during the referendum. It also states that the results of the referendum should be taken into consideration by the governments of Bougainville and PNG when they consult and discuss the political status of the former. The recommendations of the two governments are subject to the ratification of the national parliament. Given its commitment to respect and observe its obligation under the BPA, which was signed to end a violent conflict, the government of PNG and its national parliament cannot just ignore the results of the referendum. It will be less problematic on its part if the people of Bougainville decide to stay with PNG as an autonomous region. However, should an overwhelming majority votes for independence, the national government is duty bound to find a political settlement that is acceptable not only to Bougainville but also to the international community. Otherwise, it may reignite a violent secessionist war and for PNG to lose its good standing in the international community.