This research project has two interconnected goals. First, it attempts to unpack and redefine ‘hybrid regimes’ – a concept that has emerged from the ‘third wave’ democratisation literature in the late 1990s and shares with this literature its underlying cultural, ideological and teleological assumptions. I start with a critique of these dominant assumptions and point to the need to rethink hybrid regimes outside of these parameters. I then propose a more limited and lucid definition for hybrid regimes as political systems built on two contesting sources of legitimacy – elitist and popular – and corresponding institutions of guardianship and democracy. Hybrid regimes, in other words, are not ‘diminished democracies’ or ‘competitive autocracies’, but an altogether separate regime type that feature clearly defined tutelary and electoral institutions. Based on this redefinition, I present five hypotheses regarding the dynamics of change in hybrid regimes, which are subsequently applied to the two case studies: the Islamic Republic of Iran and the Republic of Turkey. The second goal of the thesis is to present a new comparative framework to analyse the post-Cold War dynamics of change in the Islamic Republic of Iran and the Republic of Turkey, two countries with political systems that scholars have found difficult to categorise and observers often treated as polar opposites due to their seemingly inimical official ideologies, Khomeinism and Kemalism. Through studying their hybrid institutional characteristics and the role of structural factors and human agency at the critical political junctures that the two countries experienced in the late 1990s and the 2000s, I endeavour to contribute to the scholarly discussion on the dynamics of interaction and legitimation between popular and elite rule.