INTRODUCTION: Equitably contributed domestic health financing is essential for making progress toward Universal Health Coverage (UHC) in Low- and Middle-Income Countries (LMICs). This PhD thesis explores how External Development Partners (EDPs) and the International Monetary Fund (IMF) influence the mix of domestic health financing sources in recipient/borrower countries through their financial and non-financial activities, including the debt and loan conditionalities that follow from loans. METHODS: The research applies a mixed-methods approach to study the research questions. This consists of an econometric cross-country panel data study and a case study in Senegal using key informant interviews, purposive document review and descriptive statistical analysis. RESULTS: At the global level, official development assistance for the health sector channelled via the government reduced both Government Health Expenditure as a Source (GHE-S) and Out-Of-Pocket payments (OOP) per Gross Domestic Product (GDP), while public external debt servicing per GDP was associated with a shift from GHE-S toward OOP out of all current health expenditure. In Senegal, EDPs, including the World Bank (WB) after year 2000, and the IMF promoted GHE-S and community-based health insurance while seeking to reduce OOP. However, past WB promotion of user fees, ongoing IMF fiscal austerity measures, debt obligations and inadequate political priority may have limited GHE-S expansion and led to a continued high reliance on OOP. CONCLUSIONS: In countries experiencing similar or worse debt burdens than Senegal, debt relief may be a necessary policy option to help generate needed fiscal space for health. Debt-for-health-swaps should be considered to ensure funds freed up also benefit the health sector, along with dedicated health spending floors in IMF programmes. Building on the work in this thesis, more country case studies should be performed of EDP+IMF influence on domestic health financing sources as well as the country-level impacts of public debt on domestic health financing.