This paper examines the factors driving the Japa syndrome among skilled young adults in Nigeria and analyses how these factors contribute to brain drain and influence the country's socio-economic development. The paper is guided by Lee's (1966) Push-Pull Theory of Migration, which explains migration as the result of factors that compel individuals to leave their place of origin and those that attract them to destination countries. Drawing on evidence from scholarly literature, government publications, and reports from national and international organisations, this narrative review indicates that unemployment, poor remuneration, insecurity, inflation, weak governance, inadequate infrastructure, and limited career advancement opportunities are the principal drivers of skilled migration from Nigeria. Conversely, competitive salaries, favourable working conditions, stronger social welfare systems, and greater opportunities for professional development continue to attract skilled Nigerian professionals to high-income countries. The persistent emigration of doctors, nurses, lecturers, and other skilled professionals has resulted in shortages of qualified personnel, weakened institutional capacity, reduced research productivity, and slower socio-economic development. Although remittances, investments, and knowledge transfers from Nigerians in the diaspora provide significant economic benefits, they do not adequately offset the long-term loss of skilled human capital. The paper concludes that addressing the structural drivers of migration through sustained improvements in governance, employment generation, investment in human capital, and better conditions of service is essential for reducing brain drain and strengthening Nigeria's capacity for sustainable socio-economic development.