Since McCombs and Shaw first introduced the theory in 1972, agenda setting has emerged as one of the most influential perspectives in the study of the effects of mass media. Broadly defined, “agenda setting” refers to the ability of mass media sources to identify the most salient topics, thereby “setting the agendas” for audiences. In telling us what to think about, then, mass media sources are perceived to play an influential role in determining priorities related to policies, values, and knowledge on a given topic or issue. Scholars have studied this phenomenon according to both object (issue) salience and attribute salience and along aggregate and individual audience responses. The audience characteristics of need for orientation, uncertainty, relevance, and involvement are advanced as moderating and predicting agenda-setting effects. When agenda-setting theory is applied to the study of messaging related to health and risk communication, scholars have reviewed and identified common themes and topics that generally include media’s role in educating and informing the public about specific health conditions as well as public health priorities and administrative policies. Agenda setting is often examined in terms of measuring mass media effects on audiences. Looking at interpersonal communication, such as that coming from medical providers, opinion leaders, or peer networks, in studies will allow research to examine the combined effects of interpersonal and mass communication. Testing possible interactions among differing sources of information along with assessment of issue and attribute salience among audiences according to an agenda-setting framework serves to document audience trends and lived experiences with regard to mass media, health, and risk communication.