This study reports on an experimental test of the effects of descriptive and injunctive norm appeals on intentions to prevent food waste in China and the United States (N = 1449), testing the role of cultural context and group orientation in this process. Results showed that the main effects of descriptive and injunctive norm messages on behavioural intentions were mediated by normative perceptions, and cultural context moderated both paths of this mediation. Specifically, with the same message exposure, Chinese participants perceived food waste prevention as more prevalent and socially approved compared to US participants. Normative perceptions interacted with cultural context to influence behavioural intentions, such that both descriptive and injunctive norm perceptions predicted stronger intentions to prevent food waste among Chinese participants compared to Americans. Group orientation yielded a main effect on behavioural intentions, instead of the moderation effects as expected. Findings suggest the need for culturally grounded and contextualized approaches to communication of social norms, as well as building cultural concepts into theories of social norms. This article is part of the theme issue 'Social norm change: drivers and consequences'.