This thesis examines the potential for transforming brain drain into brain gain through diaspora engagement, with a focus on Nigeria’s policy environment. Despite having one of the most highly educated and professionally accomplished diasporas, Nigeria struggles to convert this human capital into meaningful national development. Drawing on the Diaspora Option Theory, the study argues that institutional capacity, policy coordination, and non-financial engagement are critical to leveraging diaspora contributions. Using a comparative case study of India, Ghana, and Nigeria, it highlights the effectiveness of different engagement models and reveals the limitations of remittance-based strategies. The findings show that while cultural ties and identity-based campaigns are valuable, structured policy inclusion, co-sponsored initiatives, and sectoral knowledge networks have a greater long-term impact. The study concludes that Nigeria must institutionalize diaspora engagement beyond remittances through formalized policies, sector-specific programs, and inclusive governance structures.