Public health insurance (PHI), known for its all-inclusiveness and centralized government management, is being widely adopted to advance universal health coverage (UHC) in Sub-Saharan Africa. This doctoral thesis applies a mixed-methods approach to explore the impact of PHI on the incentives and behaviors of healthcare providers in East Africa. The first chapter investigates Rwanda’s community-based health insurance. A multisite ethnography highlights challenges in district hospitals, including increased workload, practice constraints, and delayed reimbursements. The study also reveals the negative impact of delayed payments on provider performance, stressing the need for policymakers to consider healthcare system capacity in UHC reforms. The second chapter integrates ethnographic insights to adapt an economic model and analyze the dynamics between patients, providers, insurers, and hospitals in East Africa. It finds that timely disbursement of performance-based financing improves outcomes, while payment delays demotivate providers. It also proposes cost-effective solutions to mitigate these delays. As a COVID legacy, the third chapter shifts focus to China while maintaining the thesis’s aim of understanding PHI’s supply-side effects. It examines the impact of diagnosis-related groups (DRGs) on provider performance in Zhejiang province, showing that DRGs reduce costs and hospital stays. These findings offer lessons for East African countries like Rwanda, which are considering similar reforms to sustain UHC. Overall, the thesis provides detailed insights into PHI’s supply-side effects, offering policy recommendations to address challenges like delayed payments and sustain UHC.