Although the legitimacy of public service media (PSM) is often mentioned in the context of frameworks, such as the European Broadcasting Union’s contribution to society initiative, the emphasis is rarely on the concept of legitimacy and its meanings. This chapter provides different theoretical perspectives on the concept of legitimacy and argues that to conceptualise legitimacy as perception can be particularly helpful in research investigating PSM’s potential contribution to society. To illustrate this argument, past debates in the context of public value are analysed to show how the legitimacy of PSM has been primarily understood as the result of strategic communication processes. In addition, several research questions, methodological approaches, and challenges that can be considered in research on PSM by understanding legitimacy as perception are outlined.