Corruption is often defined as the abuse of public office for private gain. This article suggests that this is inadequate for understanding corruption in weak states and presents two broader definitions of the concept. It discusses findings from qualitative and quantitative research conducted in Papua New Guinea in light of these definitions. Respondents – particularly the poor and marginalised – saw corruption as tied to the actions of public officials as well as non-state actors. It is argued that applying broader definitions of corruption could help researchers and policy makers better understand citizens’ concerns about corruption, particularly where the state is weak.