Research on policy agendas and agenda-setting has developed into an important subdiscipline of comparative politics, which seeks to understand how political actors allocate scarce attention. The theoretical origins of the field describe agenda-setting as a “conflict of conflicts,” that is the political struggle over the question of which issues receive attention. Modern scholars have expanded on these ideas and turned them into important theoretical models of the agenda-setting process. The most influential of these models are Kingdon’s multiple streams approach and Baumgartner and Jones’ punctuated equilibrium theory. The former analyses the emergence of issues in the separate streams of policies, politics, and problems, whose coupling is necessary for any issue in order to be considered for political decision-making. In contrast, the latter stresses the importance of negative and positive feedback mechanisms in order to explain long periods of incremental policy change and sudden radical changes, which characterize the policy process. Inspired by the second approach is the Comparative Agendas Project, which is a comprehensive and comparative data collection effort about policy agendas using a unified taxonomy. These data enable scholars to research the entire political process from media inputs via government throughput to legislative output. Studying governmental agendas, it is paramount to stress that—against common wisdom—political ideology does not play a decisive role in the agenda-setting process. Rather, both leftist and rightist governments seek to portray themselves as potent problem-solvers and respond to problematic societal condition in order to prove their competence. Looking at the media as one potentially powerful political agenda-setter, it turns out that newspapers and television channels’ power to steer the political agenda hinges on a variety of conditions. Generally, media outlets are most successful in setting the agenda if they report on issues that otherwise would not have been brought to the public’s attention. But even then, the media’s role appears to be restricted to narrowing down the issue menu from which politicians can choose when setting their agenda. The study of political agendas is by no means limited to these areas, as shown by the hundreds of articles that have been published in major political science journals over the past decades. While the agenda approach has not yet developed into a theory of politics, it has certainly become a major subdiscipline of comparative politics, which has helped make sense of the political world.