Purpose: This study rigorously investigates the phenomenon of human capital flight and migration in Nigeria, emphasizing the alarming exodus of skilled professionals and its profound implications for the nation's economic development. By contextualizing brain drain within the broader landscape of labour mobility, this work seeks to elucidate the factors driving the migration of educated individuals, particularly in critical sectors such as healthcare, education, and technology. Materials and Methods: Utilizing a mixed-methods approach, this research synthesizes qualitative data from academic literature, policy documents, and empirical studies, alongside quantitative analysis drawn from migration statistics and socioeconomic metrics. This robust methodological framework supports a comprehensive exploration of the interplay between migration, brain drain, and national development, facilitating a deeper understanding of the ramifications of skilled labour loss. Findings: The findings indicate that Nigeria's alarming exodus of professionals is intricately linked to a confluence of factors, including systemic corruption, deteriorating infrastructure, and limited employment prospects. This human capital flight significantly undermines the quality and accessibility of essential services in critical sectors, leading to substantial socio-economic disparities. Consequently, the loss of skilled labour constrains Nigeria's competitive edge and stunts its economic resilience and growth potential. Implications to Theory, Practice and Policy: This inquiry extends beyond descriptive analysis to propose a nuanced framework for understanding the theoretical implications of human capital flight and migration in developing economies. It underscores the urgent need for policymakers to undertake comprehensive strategies that address the root causes of this phenomenon, fostering a conducive environment that retains talent while enhancing human capital investment and innovation capacity.