Governments increasingly adopt digital platforms in their digitalization initiatives. However, existing research in government IT primarily focuses on “government as a platform” approaches without fully accounting for the roles that public agencies can assume in platform ecosystems or the varying degrees of ecosystem openness. This paper synthesizes literature in this area by asking the research question: How do public agencies strategically govern their participation in platform ecosystems? We conducted a theoretical review of 60 qualitative empirical studies published in leading government IT and Information Systems journals between 2010 and 2023. Our findings suggest that public agencies adopt a continuum of centralized to distributed governance strategies, shaped by their role as platform builders, arbitrators/catalysts, or decentralized partners, and the degree of ecosystem openness. We also identify diverse governance mechanisms implementing these strategies, including incentive structures, control mechanisms, and coordination efforts. These findings may inform the design of governance frameworks for future public-sector platform initiatives.