In 2016, Zanzibar – one of the constituent territories in the United Republic of Tanzania – introduced universal, tax-financed old-age pensions. This was (at the time) the boldest pension reform in Africa north of the Zambezi, and contrasted with the ambivalence and caution showed hitherto by the countries on the East African mainland (including, especially, Tanzania as a whole). This paper traces three distinct periods in the process leading to the reform in Zanzibar. In the first, international NGOs, working with some officials in some government departments, placed the proposal firmly on the reform agenda. In the second period, support cohered within the political and administrative elite in Zanzibar. In the third phase, the details were decided and implementation planned carefully. Specific features of the society and economy of Zanzibar were conducive to the reform: Deagrarianisation meant that the need for welfare grew whilst the opportunities to address this through household agricultural production diminished; existing charitable traditions fed into new statist programmes; political competition and (briefly) reconciliation encouraged reform. But the reform also reflected political choices made by both reformers and skeptics. Reformers built a strong coalition spanning various government departments, and were willing to compromise with fiscal conservatives over the details of the reform and hence the total cost. The case of Zanzibar shows that important welfare reforms are possible, even in low-income countries, given the combination of conducive economic, social and political conditions, and shrewd political decision-making by reformists. In the absence of similar conditions and strategies, the reform in Zanzibar may not be widely replicated.