The theme of this research is smart power in Iran’s foreign policy toward Arab national security in the Middle East [Lebanon, Iraq, and Yemen]. This important and influential topic was explained and analyzed on the regional and international political scene. Also, it highlighted how the IRI managed in employing this type of power in its foreign policy with the purpose to penetrate Arab national security and exporting its Islamic revolution to the Arab surrounding, and the gains it had made, in accordance with the directives of the Supreme Leader Ayatollah Khomeini, and in line with what is stipulated in the constitution of the Islamic Republic of Iran 1979. The study examined the case studies of Lebanon, Iraq, and Yemen during the time period (2003- 2015), where 2003 witnessed a significant turning point that contributed to reviving Iran’s dual-strategy to expand in the Arab world and reshaping its map and regimes in preparation for exporting its Islamic revolution to it and extending its control over it, relying on its hard and soft power instruments on the one hand, and taking advantage of some regional and international shifts that turned the balance of power in favor of Iran - such as the US-led occupation of Iraq, the strategic buffer for the Arab region, in addition to the outbreak of the Arab Spring in late 2010, which crowned in the Iranian-backed Houthis group’s seizure of the Yemeni capital, Sanaa, in late 2014- that made the Middle East a fertile soil and conducive atmosphere to the implementation of Iranian agendas on the other hand. The research depended on Nay’s smart power model and Waltz’s neo-realism theory, as exclusive analytical frameworks. As well an interpretive case study was utilized as the main research method whose findings were derived from primary and secondary databases. The research concluded that the IRI had succeeded in employing smart power in its foreign policy, enabling it to occupy three Arab countries, which are considered fundamental pillars of Arab national security. This, in turn, has proved beyond the shadow of a doubt that the IRI poses an existential danger and a serious threat to the Arab nation and its national security, as evidenced by the research databases.