This systematic literature review provides a deep analysis of the interrelationships among corruption, fiscal leakages, and governance collapse in Nigeria from 2018 to 2025. Besides, it is built on 64 peer-reviewed articles, institutional reports, and doctoral theses obtained through Google Scholar, Scopus, Web of Science, AJOL, and ResearchGate with PRISMA 2020 methodology, the research combines strong econometric, audit, and survey proofs to assert that corruption and fiscal leakages are not just symptoms but even primary structural drivers of the breakdown of the government. Among the major findings are the annual loss of US$40.9–64.7 billion through illegal financial flows, oil theft, and tax evasion; regression coefficients showing that the perception of corruption and tax evasion together account for 73–91 % of the shortfall in the non-oil revenue and the stagnation of human development as well as the forsaking of over 13,000 projects despite allocation of trillions of naira. The review has shown that the whole process is self-reinforcing. The cycle of elite impunity, institutional opacity, and failure of collective action becomes a rentier-pre-bendal state, thus eroding public trust and perpetuating multidimensional poverty for 133 million citizens. The application of principal–agent, rentier-state, and collective-action theories leads to the conclusion that there has been a failure of incremental reforms and only radical and simultaneous interventions, such as real-time fiscal transparency, independent anti-corruption institutions, e-procurement mandates, and enforced diversification away from oil, can disrupt the cycle and prevent deeper state fragility by 2030. The research provides a roadmap, grounded in evidence, for dismantling graft and rebuilding governance in Nigeria, offering policymakers and researchers a clear direction.

 Keywords: corruption, fiscal leakages, governance failure, illicit financial flows, rentier state, Nigeria, systematic review.