During the past three years, Yemen has witnessed a number of political and social transformations, foremost among which was the ousting of former President Ali Abdullah Saleh, from power. Although he was the main patron of tribal elites, no significant change in tribal participation has occurred. Many tribal leaders still receive financial allocations from the Presidential Office. Appointments to senior positions remain based on tribal status and tribal equilibrium, and many tribal elders retain direct and indirect influence on decision-making processes. Tribal leaders are concerned with the outcomes of the National Dialogue Conference and its proposed changes: from a unitary to a federal state, the shift from single winner to an electoral system based on proportional representation, and from a presidential to a parliamentary system of government. These transformations, that will lead to a reorganization of the rules and institutions that regulate the distribution of political power, threaten tribal leaders’ political strength. Growing opportunities available to political parties are likely to reduce these leaders’ chances of winning elections. Hence, some tribal leaders have embarked on the establishment of political parties, like the Justice and Construction Party, established by Sheikh Mohammed Ali Abu Lohoum, the National Solidarity Party, established by Sheikh Hussein al-Ahmar, and the Yemeni Union Rescue Party, established by Sheikh Arafj Hadhban. Moreover, the emergence of the Ansar Allah Movement (Houthis) as a new player on the social and political map of Yemen, and continuing conflicts between Sunnis and Shi’as may lead to changing boundaries and the dominance of sectarian identities at the expense of tribal identities (that is if they have not already done so). This factor is likely to lead to a decline of the social and political roles of tribal leaders in areas under their control. This paper analyzes the potential effects of social and political transformations currently taking place in Yemen and the political role of Yemeni tribes in general, and tribal leaders in particular. It deals with the defensive mechanisms that will be used by tribal leaders to resist these changes and reduce their declining political roles. It also discusses the results of these changes at the levels of the democratic transition in Yemen, the completion of state institutionalization, and government effectiveness and its ability to perform its functions.