Background <p>Financing fragmentation in health systems refers to the coexistence of uncoordinated financing and payment control mechanisms that hinder the achievement of universal health coverage. This study aimed to identify the political and institutional determinants of the Colombian health system’s financing fragmentation, based on the experiences and perceptions of health sector stakeholders and policymakers.</p> Methods <p>An exploratory qualitative study was conducted. A total of 28 stakeholders and policymakers, including government officials, elected politicians, healthcare insurance and provider managers, and health-professional-association representatives, participated in semi-structured interviews. Initial coding and categorization (deductive analysis) were performed, followed by data clustering and content analysis (inductive analysis) using a framework analysis approach. Synthesis was graphical and narrative.</p> Results <p>From the interviewees’ perspective, the political determinants that may perpetuate the Colombian health system financing fragmentation were: governance issues, including corruption, armed conflict, poor debate and political polarization, decisions made by politicians without adequate knowledge of the health system, limited civil society participation, media influence, and lack of funding for the immigrant population’s healthcare. The institutional determinants were: corruption, underfunding of the system, poor information systems, limited research, resource management by insurers, vertical integration, and the medical-industrial complex’s role.</p> Conclusions <p>The results suggest that financing fragmentation in the Colombian health system has determinants rooted in social struggles, armed conflict, and state-society interactions. Addressing these determinants requires political commitment, stronger governance, civil society engagement, and technically skilled decision-makers to develop public policies that ensure integrated financing, robust resource monitoring, and interoperable information systems to achieve universal health coverage.</p> Patient or public contribution <p>To identify the political and institutional determinants of financing fragmentation in the Colombian health system from the perspectives of stakeholders and policymakers, this study included elected politicians, government members, health insurance and provider managers, and health professional association representatives involved in the formulation, regulation, implementation, or debate of healthcare reforms.</p>