Social norms and social preferences have increasingly become an integral part of the economics discourse. After disentangling the two notions, this chapter focuses on social norms, which we stipulate as group-specific solutions to strategic problems. More precisely, we define social norms as behavioral regularities emerging in social-dilemma games, as a result of preferences for conformity conditional on an endogenous set of beliefs and expectations. To that end, we review models that explicitly feature normative expectations, as well as models that account for category-specific prescriptions. We finally survey some relevant experimental evidence.