The role of social norms in influencing human behavior is widely recognized in philosophy and social and behavioral sciences. Interest in harnessing their influence has spurred a variety of behavioral interventions that specifically target social norms for policy purposes. These social norm interventions have been applied to an increasing number of health-related and environmental behaviors. However, there is currently no systematic understanding of them as a distinct form of policy. This is partly because different interventions are based on theories of social norms that each define them differently and focus on different aspects of their influence. The fragmented nature of the field makes it difficult to assess the general features of social norm interventions, such as which conditions determine their suitability and effectiveness, and what type of ethical issues are related to social norm interventions specifically. This dissertation clarifies the nature of social norm interventions by addressing the following questions: What are social norms and how do they influence behavior? In which ways can the influence of social norms be intervened on to achieve behavioral change? How should social norm interventions be evaluated ethically? It develops a unified account of social norm interventions that is useful for philosophers and theoreticians seeking to better understand social norms and their influence, and also for practitioners who wish to make informed and responsible policy decisions.

2024