Legitimacy is important to governance, yet we know little about how it develops. This article examines an initial step???how citizens come to use the same criteria to evaluate legitimacy. Earlier studies have identified the state and society as sources of possible legitimacy criteria but have not explained the process by which citizens adopt them. Comparative Politics July 2016 This article offers a framework to help understand this process. Specifically, it argues that citizens embrace ideas as legitimacy criteria based on the credibility of the messengers and the utility, fit, and success of the ideas. Original survey, in-depth interviews, and observational data from Central Asia as well as published accounts of government leaders' and societal forces' ideas and actions in the region illustrate the argument.