Medical associations not only organize their members' interests but also exercise professional authority within the field of health policy. An important aspect of professional authority is the medical profession's ability to position itself in relation to national health policy and whether its command of professional knowledge enables the profession to claim exclusive authority for reflecting on health policy. This article analyzes and compares how medical associations claim authority over health policy and how they reposition their claims in light of perceived contestations to medical authority in public debates or from the political system. The study is based on a qualitative, descriptive analysis of 975 editorials in the medical associations' lead journals in the United States, the United Kingdom, and Denmark over a period of 60 years. The analysis explores the trajectories of authority claims in the three countries and how professional authority claims may be reconfigured to reflect external changes in health policy institutions. Whereas all the medical associations were highly critical of state-organized health systems in the 1950s and early 1960s, the British and Danish associations seem to shift positions entirely after national health systems are gradually implemented and the associations begin to present themselves as these public institutions' strongest supporters.