BackgroundGovernance arrangements include changes in rules or processes that determine authority and accountability for health policies, organisations, commercial products and health professionals, as well as the involvement of stakeholders in decision-making. Changes in governance arrangements can affect health and related goals in numerous ways, generally through changes in authority, accountability, openness, participation and coherence. A broad overview of the findings of systematic reviews can help policymakers, their technical support staff and other stakeholders to identify strategies for addressing problems and improving the governance of their health systems.ObjectivesTo provide an overview of the available evidence from up-to-date systematic reviews about the effects of governance arrangements for health systems in low-income countries. Secondary objectives include identifying needs and priorities for future evaluations and systematic reviews on governance arrangements and informing refinements of the framework for governance arrangements outlined in the overview.MethodsWe searched Health Systems Evidence in November 2010 and PDQ Evidence up to 17 December 2016 for systematic reviews. We did not apply any date, language or publication status limitations in the searches. We included well-conducted systematic reviews of studies that assessed the effects of governance arrangements on patient outcomes (health and health behaviours), the quality or utilisation of healthcare services, resource use (health expenditures, healthcare provider costs, out-of-pocket payments, cost-effectiveness), healthcare provider outcomes (such as sick leave), or social outcomes (such as poverty, employment) and that were published after April 2005. We excluded reviews with limitations that were important enough to compromise the reliability of the findings of the review. Two overview authors independently screened reviews, extracted data and assessed the certainty of evidence using GRADE. We prepared SUPPORT Summaries for eligible reviews, including key messages, 'Summary of findings' tables (using GRADE to assess the certainty of the evidence) and assessments of the relevance of findings to low-income countries.Main resultsWe identified 7272 systematic reviews and included 21 of them in this overview (19 primary reviews and 2 supplementary reviews). We focus here on the results of the 19 primary reviews, one of which had important methodological limitations. The other 18 were reliable (with only minor limitations).We grouped the governance arrangements addressed in the reviews into five categories: authority and accountability for health policies (three reviews); authority and accountability for organisations (two reviews); authority and accountability for commercial products (three reviews); authority and accountability for health professionals (seven reviews); and stakeholder involvement (four reviews).Overall, we found desirable effects for the following interventions on at least one outcome, with moderate- or high-certainty...