In the modern world, government policy makers engage in the decision making process to pursue the interests of their countries. Think tanks play a significant role in this complicated process by giving advice to decision makers. Since the beginning of the twentieth century, think tanks increasingly emerged in the world, especially in Western European countries and the United States of America (USA). Israel, since its illegal establishment, created various think tanks to serve its political and security interests in the Middle East. Making peace with Middle Eastern countries and strengthening ties with the USA are the most crucial goals of Israel's foreign policy. Nevertheless, since its establishment, Israel adopted an aggressive approach towards Palestine, Lebanon, and recently Iran. Therefore, the main questions addressed in this article are as follows: What is the impact of Israeli think tanks on its foreign policy from 2000 to 2017? The Rational Actor Model, the Poliheuristic theory and Groupthink theories have been used to explain how think tanks influence policy makers in Israel. In order to conduct the research, the authors have chosen case study method as a qualitative method. In fact, the authors have considered Israeli think tanks as a case study to examine its impact on Israeli foreign policy. The hypothesis of the article is therefore the following: In recent decades, Israeli think tanks have persuaded Israel regime to formulate its foreign policy on the basis of aggressive approach, as witnessed in the Lebanon war (2006), the Gaza war (2008-9) and (2014), and Israel’s countering of Iran.