Maxwell McCombs and Donald Shaw’s pioneering study on the agenda-setting approach is both theoretically and empirically rather simple, but has nevertheless revolutionized media effects research. The assumption that the public considers those political issues most relevant that are most frequently covered by mass media remains the most widely studied hypothesis in media effects research to this day. Over the past 50 years, the approach has been continuously refined and has not lost its societal relevance, even in the digital age. This article first summarizes the key findings of this seminal study and then outlines the further development of the agenda-setting approach up to the present. The focus is on current developments in the context of digitalization and the societal implications of the approach.