BACKGROUND: In 2018, Kenya's Ministry of Health (MoH) gazetted the Health Benefits Package Advisory Panel (HBPAP) to develop a benefits package for its universal health coverage (UHC) programme. In this study, we examine the political process that led to the gazettement of the HBPAP. METHODS: We conducted a case study based on semi-structured interviews with 20 national-level participants and, reviews of documents such as organizational and media reports. We analyzed data from the interviews and documents thematically using the Braun and Clarke's six step approach. We identified codes and themes deductively using Kingdon's Multiple Streams Theory which postulates that the successful emergence of a policy follows coupling of three streams: the problem, policy, and politics streams. RESULTS: We found that the problem stream was characterized by fragmented and implicit healthcare priority-setting processes that led to unaffordable, unsustainable, and wasteful benefits packages. A potential policy solution for these problems was the creation of an independent expert panel that would use an explicit and evidence-based healthcare priority-setting process to develop an affordable and sustainable benefits package. The political stream was characterized by the re-election of the government and the appointment of a new Cabinet Secretary for Health. Coupling of the problem, policy, and political streams occurred during a policy window that was created by the political prioritization of UHC by the newly re-elected government. Policy entrepreneurs who included health economists, health financing experts, health policy analysts, and health systems experts leveraged this policy window to push for the establishment of an independent expert panel as a solution for the issues identified in the problem stream. They employed strategies such as forming networks, framing, marshalling evidence, and utilizing political connections. CONCLUSION: Applying Kingdon's theory in this study was valuable in explaining why the HBPAP policy idea was gazetted. It demonstrated the crucial role of policy entrepreneurs and the strategies they employed to couple the three streams during a favourable policy window. This study contributes to the body of literature on healthcare priority-setting processes with an unusual analysis focused on a key procedural policy for such processes.