Despite a proliferation of research on legitimacy, the ‘grey area’ that lies between legitimacy and illegitimacy remains undertheorized. Responding to calls for further research, we clarify the construct of legitimacy and extend legitimacy theory by providing a conceptual framework for analyzing the legitimacy-illegitimacy continuum. First, we propose three novel legitimacy states between legitimacy and illegitimacy: conditional legitimacy, unknown legitimacy, and conditional illegitimacy, and elaborate on the distinct qualitative characteristics of the five legitimacy states. Second, we offer a model of the dynamics of legitimacy state change and the (in)stability of the issue-specific reference framework that is used to judge them. Third,...