The 1995 Constitution of the Federal Democratic Republic of Ethiopia redesigned the new country’s federal structure according to ethnic lines and formally guaranteed the right of self-determination for every Ethiopian ethnocultural group. But not all the ethnic communities were allowed to administer their own state-region and, furthermore, to exercise the right of self-determination. This is the case of the Sidama ethnocultural group which, after two attempts, one of that failed and one still in progress, does not have the opportunity to exercise political autonomy over an own territorial region. The Sidama self- determination process’ evolution and their race to a political and regional autonomy represent a systemic gap within the federal model acquired in 1991, a contradiction between the federal rule of law and the pressures of a government that acts as if it were in power of a unitary and centralized state. Following this relevant issue at the core of this federal prototype’s assumption, this thesis aims to analyse if ethnic federalism formula could guarantee equal rights and freedom to all the Nations, Nationalities and Peoples of Ethiopia and could provide a solution to face the Ethiopian ethnocultural groups’ requests of self-determination. The still ongoing process of self-determination demanded by the Sidama people will be a fundamental element to study and to evaluate the Ethiopian federal model and its impact on the ethnonationalist claims.