Brazil’s nuclear programme reflects the complex challenges faced by Global South nations in achieving scientific and technological autonomy. Despite its significant natural resources and decades-long commitment to nuclear development, the country has struggled with institutional, financial, and systemic barriers that undermine its progress. This study highlights the critical role of policy discontinuity, unstable funding, and weak integration between the state, the productive sector, and academia in delaying Brazil’s nuclear ambitions. Adopting an institutionalist perspective, it underscores how these structural factors impact the sustainability of science and technology policies, contrasting with traditional analyses that emphasise strategic and geopolitical concerns. The findings suggest the need for comprehensive reforms prioritising policy continuity, innovation, and collaboration to enable Brazil and similar emerging democracies to overcome these limitations and advance their scientific and technological development.