This study examines the trajectories of the Biafra (located within current Nigerian territory) and  South Sudan self-determination movements through qualitative analysis of interviews, surveys,  and document sources. The research employs a triangulated data approach, including thematic  analysis of 10 in-depth interviews with activists and scholars (7 for Biafra and 3 for the South  Sudan movement), survey responses from 23 participants (19 for Biafra and 4 for South Sudan),  and critical review of archival documents and scholarly articles. Findings reveal that both  movements emerged from profound historical grievances, including colonial-era marginalization,  postindependence genocide narratives, and systematic socioeconomic exclusion. While South  Sudan achieved independence through a combination of unified leadership under John Garang,  sustained armed resistance, and decisive international support (particularly from the US and  regional allies), Biafra's struggle was hampered by fragmented leadership, geopolitical isolation, and Nigeria's military superiority backed by Cold War powers. The study highlights three critical  success factors in self-determination movements: (1) cohesive internal organization, (2) strategic  international alliances, and (3) effective framing of grievances. Analysis further reveals how differential access to diplomatic recognition and arms supplies shaped outcomes, with South Sudan benefiting from post-9/11 geopolitical shifts absent in Biafra's 1960s context, which was exacerbated by post-Cold war politics.