["The British Journal of Sociology, Volume 72, Issue 4, Page 1092-1112, September 2021. ", "\nAbstract\nWhen the Arab Spring gave way to demonstrations in Syria in 2011, the Kurds in the country were also full of hope. While they were going into the streets, the Kurdish political parties were debating what their people should do and offering competing visions for the future. Then in July 2012, the regime unexpectedly withdrew its forces from the Kurdish regions (Rojava). Suddenly, a revolutionary situation emerged in Rojava: a mobilized population and several political parties claiming leadership and offering competing political projects for a new society. Among these parties, only the Democratic Union Party (PYD) managed to move into the power vacuum and establish its control over large areas. Its rivals were unable to stop the rapid rise of this relatively young organization and fast erosion of their own base. How did the PYD manage to become the dominant organization even though it had rarely drawn attention before the civil war? This question raises the larger problem of how a revolutionary organization becomes the dominant one among competitors. Even though multiple organizations competing in a single revolution is a recurrent phenomenon, we still lack a comprehensive framework specifically focusing on this issue. In this paper, I argue for an approach based on legitimation: for people to follow a certain organization over others, they should see it as a legitimate leader. Bringing together the insights of the political and organizational legitimacy literatures, I identify three processes of legitimation for revolutionary organizations: ideological/normative congruence, effective organizational capacity, and accumulation of prestige. Drawing upon participant observation and 30 in‐depth interviews with Kurdish individuals collected during fieldwork in Iraq, Germany, and the United States between 2016 and 2019, I demonstrate that the PYD has outperformed its contenders and managed to legitimate its leadership through these three processes.\n"]