The Shia clergy in Iran have long had an interest in the Shia population of Lebanon. Clergy for the Lebanese Shia communities were trained in Iran before the Revolution, and intermarriage between clerical families in both countries had been occurring for several generations. Lebanon's most prominent Shia cleric, Imam Musa as Sadr, who mysteriously disappeared in 1978 while on a trip to Libya, was born in Iran into a clerical family with relatives in Lebanon, a fact that facilitated his acceptance in the latter country. Musa as Sadr was a political activist, like so many clerics of his generation trained in Qom and An Najaf, and he succeeded in politicizing the Lebanese Shias. Thus, it was natural that the Shia community of Lebanon should become one of the earliest to which Iranian advocates of exporting revolution turned their attention. Their analysis of the political situation in Lebanon in 1979 and 1980 convinced them that the country was ripe for achieving an Islamic revolution and that conditions were also favorable for eradicating Israel and recreating Palestine.

The main constraint on Iran's political involvement in Lebanon was Amal, the political organization established by Musa as Sadr. After Sadr's disappearance, Amal had fallen under the influence of secularized Shias who preferred the political integration of the Shia community within a pluralistic state and regarded the Iranian vision of Islamic revolution as inappropriate for Lebanon. The Israeli invasion of southern Lebanon in 1982, however, provided Iran an opportunity to circumvent Amal's domination of the Shias. Syria permitted a contingent of several hundred Pasdaran members to enter Lebanon, ostensibly to help fight against Israel. The Pasdaran established posts in the eastern Biqa Valley and from there proselytized on behalf of Islamic revolution among poor and uprooted Shia young people. The ideas of Islamic revolution appealed to many of the Shias who were recruited by new political groups such as Islamic Amal and the Hizballah, both of which opposed the comparative moderation of Amal. The support of the Pasdaran provided these groups with a direct link to Tehran, and this permitted Iran to become one of the foreign powers exerting influence in Lebanon. In 1987 an estimated 500 member of the Pasdaran were in Lebanon.

Data as of December 1987