<p>This paper examines standard setting in health professions education through the lens of historical epistemology. Rather than treating standard setting as a neutral technical procedure, we analyse how it became thinkable as a distinct assessment practice and how its forms have shifted across different historical contexts, driven by evolving concerns and epistemic assumptions. We develop a five-part analysis of historically situated <i>epistemic regimes</i> of standard setting, spanning forms of threshold judgement in which standards were operative but not yet explicit, through prescriptive, predictive, and performative approaches, to the contemporary landscape of programmatic assessment and entrustment. Across these regimes, standard setting practices are informed by changes in styles of reasoning, characteristic questions, forms of authority, and modes of justification that shape what counts as minimum competence, how it is determined, and who is authorised to judge. Our central argument is that standard setting is historically contingent and epistemically constructed, while remaining indispensable to assessment practice. Recognising this does not weaken standard setting; rather, it clarifies the assumptions about evidence, expertise, authority, and acceptable risks embedded in different methods, situates those methods within shared professional commitments and historically shifting interpretations of competence, and makes their justificatory bases more explicit. We argue that standard setting practices are best understood and defended through contextually grounded validity arguments, informed by epistemological reflection and attentiveness to historicity.</p>