From the dawn of the 1978-79 Iran revolution until the consolidation of Hizbollah in the late 1980s, a network of Iranian, Lebanese, and Palestinian clerics played a crucial role in spreading the Iranian Revolution to Lebanon. This paper argues that the universal ideas of the Revolution and the June 1982 Israeli invasion of Lebanon galvanized these Shi'i and Sunni ulama to join ranks and establish the Association of Muslim Ulama in Lebanon (Tajammu al-Ulama al-Muslimin fi Lubnan). The Association and then Hizbollah, both rooted in the Revolution’s internationalism, emerged out of the devastating invasion and evolved, as this paper explores in the Iranian and Lebanese contexts, along two diverging paths in the 1980s. This research explores how these clerics struggled in a supranational context for an Islamic solution to sectarian inequalities and the Israeli occupation. While the historiography of the post-1979 Iran-Lebanon relationship is primarily focused on Hizbollah, the present study shows that the internationalist ecumenical ulama played a leading role in spreading the example of the Revolution to Lebanon and became a prelude to the formation of Hizbollah. This paper relies on archival research in Iran and Lebanon as well as oral history interviews with key Iranian, Lebanese, and Palestinian individuals, who were part of the internationalism of the 1978-79 revolution. The interviewees include clerics, former members of the Revolutionary Guards, and diplomats as well as the leaders and activists of the Sunni and Shi'i groups in the region who were affiliated with Iranians before and after 1979. Despite the diminishing appeal of Iran’s policies among Sunni forces, this paper shows the importance of ecumenicalism in the formative years of the Islamic Republic and its involvement in the region and Lebanon. Thus, it challenges sectarian narratives that either question the exportability of the 1978-79 revolution (because of the specifically Shi'i and Persian identity of Iran) or confine its internationalism to Shi'i communities outside Iran.