Corruption, the abuse of entrusted power for private gain, has long been understood to respond to costs and benefits as shaped by the law. Increasingly, informal norms are also receiving attention as drivers of corrupt behavior and as potential policy targets to combat corruption. This chapter surveys existing scholarship about how informal norms affect behavior, how they interact with the law, and how they might be influenced through policy interventions to combat corruption. The reader seeking fully crafted answers and policy recipes will not find them here. Instead, this chapter aims to highlight promising ideas, suggestive evidence, and avenues for future research and policy development.