This research report presents empirical findings from an ethnographic study of the role of informal social norms in reducing corruption in public and private schools in Hanoi. The study begins by building a theoretical framework that inculcates the significance of local informal social norms in analysing/understanding corruption and designing counteraction strategies, especially at the sub-national or local level. After a two-month ethnographic study in Hanoi, a rich stock of ethnographic data was collected through observations and informal interviews. The informal social norm and practices found in various public and private schools in Hanoi included parents’ payment of teachers for extra classes to ensure better school results for their children, showing gratitude and respect to teachers by providing them with gifts on 5-6 occasions per school year, and parents’ contribution of money towards the provision of equipment in school classrooms. Our findings suggest that within the context of the school system, these informal norms persist as pragmatic responses to the weaknesses in the country’s educational system. Consequently, they are not in themselves dysfunctional or corrupt, and are widely accepted as the "normal things to do". Notwithstanding, some of the parents and teachers also admitted that these informal norms and practices sometimes result in unequal and discriminatory treatment of students whose parents cannot afford to conform to them. Consequently, they sometimes become dysfunctional and/or corrupt practices that hinder the quality of education. Hence, from a collective action perspective, we argue that efforts to reduce the levels of corruption resulting from the dysfunctional aspects of these informal norms and practices must acknowledge them as institutionalised social practices that are part and parcel of everyday life. Therefore, anti-corruption interventions must not focus on eradicating/suppressing these informal social norms entirely, as this might threaten social fabrics. Instead, anti-corruption interventions should actively engage teachers, parents and school administrators in reforming the dysfunctional aspects into functional norms and practices in line with educational quality.