The health sector has long been identified as being one of the most corrupt in high-, middle- and low-income countries. It faces particular challenges given competing incentives of public and private providers, knowledge asymmetry between providers and patients/clients, and the vulnerability of those seeking care. Corruption takes different forms, including informal payments, absenteeism, medicine theft, fraud and bribes for professional advancement. This working paper contributes to the debate on corruption within health systems in low- and middle-income countries by reviewing theory development and empirical evidence on the ways in which social structures and political economy factors drive corrupt provider practice in sub-Saharan Africa. It explores conditions that enable corrupt activities among health workers – examining evidence on the morality or justifications for corruption – and how these relate to the health system, social structures and the political economy in particular contexts.