Similarities and differences in ideologies of state leaders may determine cooperation or discord between them and the states they represent. This thesis will look into the ideologies of Israeli and Iranian leaders and their influence on the perception of threat of both states between the years 2006 and 2015. This time frame has been deliberately chosen since there was a change in the leadership with different ideological approaches in both Israel and Iran during this period. In 2009, Benjamin Netanyahu replaced Ehud Olmert as Prime Minister of Israel. Although both Olmert and Netanyahu had been together in center-right Likud until 2006, shortly before Olmert became Prime Minister he left to the centrist party Kadima. In 2013, after eight years of the rule of the conservative President Mahmoud Ahmadinejad, the moderate President Hassan Rouhani took over. Therefore, this thesis is a comparative study of the Israeli and Iranian leader’s ideologies and their impact on the relations of the two states. Moreover, the thesis will also compare the differences between the Israeli Prime Ministers, respectively Iranian Presidents. This thesis aims to determine whether ideologies of the leaders of Israel and Iran influence their perception of threat between each other and thus the relations between them. Research Questions: Do the ideological differences of the Israeli and Iranian leaders between the years 2006 and 2015 influence their perception of threat between each other and thus shape the relations between Israel and Iran? Does the different ideological background of President Rouhani from President Ahmadinejad influence the perception of threat by Israel? Does the different ideological background of Prime Minister Netanyahu from Prime Minister Olmert influence the perception of threat by Iran? Hypothesis: The perception of threat between Israel and Iran is higher when the ideological discord between the Israeli Prime Ministers and the Iranian Presidents is wider. If there is an intersection between their ideologies, the perception of the threat between the countries should be lower. Literature: Haas, M. L. (2012). The Clash of Ideologies: Middle Eastern Politics and American Security. New York: Oxford University Press. Haas, M. L. (2005). The Ideological Origins of Great Power Politics. Ithaca and London: Cornell University Press. Juneau, T. (2014). Iran under Rouhani: Still alone in the World. Middle East Policy , 21 (4), 92-104. Kaye, D. D., Nader, A., & Roshan, P. (2011). Israel and Iran: A Dangerous Rivalry. Santa Monica: RAND Corporation. Leslie, J. G. (2017). Netanyahu's Populism: An Overlooked Explanation for Israeli Foreign Policy. SAIS Review of International Affairs , 37 (1), 75-82. Parsi, T. (2008). Israeli-Iraninan relations assesed: Strategic competition from the power cycle perspective. In H. Katouzian, & H. Shahidi (Eds.), Iran in the 21st Century: Politics, economics and conflict (pp. 136-157). New York: Routledge. Parsi, T. (2007). Treacherous Alliance: The Secret Dealings of Israel, Iran, and the United States. New Haven and London: Yale University Press.