Professions are regulated in the public interest, but precisely what the term “public interest” means can vary across time and place. Research exploring changes to professional regulation in the West has begun to identify such shifts: for instance, highlighting the emphasis on consumer satisfaction and public protection over other potential meanings of the public interest. To understand these societal shifts and their implications for professional regulation, this article first reviews neo-Weberian theories of rationalization, and empirical literature. Subsequently, it presents findings from interviews with regulatory leaders across six Canadian provinces to determine if the trends in rationalization identified are reflected in leaders’ accounts of professional regulation in the public interest. Interviews reveal that many leaders define the public interest in ways consistent with technical rationality, including a safety lens and consumer orientation; however, there is also evidence of broader meanings and values. The implications of these findings are discussed.