Conditioned domestic financing policy, referring to the domestic financing of health projects, programs, and national responses conditioned by global health funding agencies and recipient country governments, is one mechanism to promote sustainability and country ownership. We aim to understand how the concept is defined and operationalized by agencies and how such policies relate to overall health spending patterns. We first landscape the conditioned domestic “co-financing” policies and related accountability mechanisms of selected agencies. Next, applying quantitative analysis of publicly available data, we examine two agencies—Gavi and the Global Fund to Fight AIDS, Tuberculosis, and Malaria (GFATM)—to analyze the magnitude of conditioned domestic financing, relative to external assistance for health, and separately, to domestic general government health expenditure. We find wide variation in agency definitions and policies for domestic obligations in terms of what is required, reported, and accounted. The quantitative analysis highlights potential discrepancies between de jure policies and how they are de facto implemented. The results raise questions about how these policies are operationalized in terms of overall budget space for health and overall domestic sustainability planning. Both global and domestic policymakers should consider sector-wide domestic government financing for health to address the current conditioned domestic “co-financing” policies.