This study explores the role of peer communication in normative social influences on risk behavior. We use the theory of normative social behavior (TNSB) as a guiding framework for developing a communication perspective on normative social influences. Peer communication is conceptualized as a norm-building factor and its concrete role is specified as a function of its content. The hypotheses on peer communication’s impact on norms in normative social influences are tested for the case of speeding in road traffic. The analyses are based on representative survey data of 1,138 German young car drivers. Findings from mediational analyses indicate that peer communication plays a crucial role in the formation of social norms which, in turn, affect risk behavior, and that the communication’s health-promoting potential depends on its content. Implications for further norm-based theory development and strategic risk communication are discussed.