Muhammad Riza Pahlavi, Shah of Iran (r. 1941-1979), had long desired an expanded regional role for his rapidly developing nation. By the late 1960s, he had finally obtained the necessary means to further his objectives, and with announcement of the Nixon Doctrine (July 1969) followed by the well-chronicled Nixon-Kissinger visit to Tehran in May 1972, the ruler received American blessing for the maintenance of a stable, pro-Western order around the shores of the Persian Gulf. Beginning in 1971 the shah expanded Iranian influence through a variety of actions, including economic assistance, loans of military equipment, or direct intervention, as in Pakistan, Afghanistan, Iraq and the Arab sheikhdoms along the Gulf. One of his most determined and successful interventions came in Oman from 1971-1976. In response to a request from Sultan Qabus, Tehran initiated a major deployment of troops and materiel to combat the Marxist rebels in Dhufar province, who were receiving support from, among others, China, the Soviet Union and Iraq. The shah feared that the success of the rebels would lead to establishment of a hostile regime across the Straits of Hormuz, which would interrupt the flow of Persian Gulf oil. Iran remained involved there to the eve of the Islamic Revolution, although most imperial troops departed soon after the sultan declared victory at the end of 1975. Many agreed that the Iranian contribution had assured victory. For neighboring Arab states, especially Saudi Arabia, however, Iran’s intervention elicited a continuous chorus of complaints, all rooted in suspicion of the shah’s larger ambitions. US diplomats did what they could to allay these concerns, determined to avoid at all costs direct US military intervention. In this case, the shah had proven to be an able surrogate, serving American interests while furthering his own. Drawing on recently declassified documents in US and British archives as well as a variety of published materials in Persian and Arabic, this paper will examine the complexities of Iranian foreign policy in what was arguably the most sensitive region of the Middle East.