This study explores the mass emigration from Nigeria to the United Kingdom, commonly referred to as ‘Japa,’ and its implications for Nigeria’s political economy. The research employs a documentary method, analysing secondary data sources through qualitative content analysis. The study is grounded in the push-pull theory, which posits that adverse conditions in Nigeria act as ‘push’ factors, driving individuals to seek better opportunities abroad, the ‘pull’ factors. The findings reveal that unemployment, and uncertainty about Nigeria’s economic and political future are significant push factors fueling the mass exodus of Nigerians to the UK. The brain drain associated with this phenomenon has profoundly impacted Nigeria’s political economy, resulting in the depletion of skilled labour, loss of human capital, reduced productivity, and stagnated innovation. Furthermore, the study highlights the economic implications, including diminished GDP contributions, diversion of funds for medical tourism, and loss of educational investments. The research recommends economic diversification, job creation, enhanced governance, political stability, investment in education and infrastructure, incentives for skilled professionals, diaspora engagement, and international cooperation to mitigate the challenges of mass migration and brain drain. These strategies aim to address the root causes of emigration and facilitate brain gain.