In this Health Policy article, we selected and reviewed evidence synthesised by nine knowledge networks established by WHO to support the Commission on the Social Determinants of Health. We have indicated the part that national governments and civil society can play in reducing health inequity. Government action can take three forms: (1) as provider or guarantor of human rights and essential services; (2) as facilitator of policy frameworks that provide the basis for equitable health improvement; and (3) as gatherer and monitor of data about their populations in ways that generate health information about mortality and morbidity and data about health equity. We use examples from the knowledge networks to illustrate some of the options governments have in fulfilling this role. Civil society takes many forms: here, we have used examples of community groups and social movements. Governments and civil society can have important positive roles in addressing health inequity if political will exists.