There has been considerable academic interest in the adoption of sustainable resource management practices from a behavioural perspective, particularly in relation to the activities of community-based natural resource management (NRM) groups such as Landcare. Community groups are said to be generating new forms of social capital via their networks of relationships between individuals and groups. These connections facilitate social learning and build community capacity to address environmental problems but perhaps because of the focus on networks, the norms component of social capital has been given little attention in the NRM literature. This paper addresses that gap by synthesizing relevant social norms theory with the findings from a study examining landholder management of native vegetation in an Australian rural community undergoing substantial social change. Findings from interviews with landholders and government agency personnel indicated that existing social norms were influencing newer landholders and that new norms of land management behaviour had emerged. We suggest that there is potential to enhance the outcomes of NRM investment using interventions which capitalize on the power of social norms.