The Anglo-Iranian oil crisis of 1950–4 provides an ideal case-study for those interested in the postwar Anglo-American Special Relationship. This article investigates the oil crisis with two purposes in mind: first, to demonstrate how Britain and the United States struggled to adjust their bilateral relations in response to their changing postwar world positions; second, to show just how crucial both countries perceived the Special Relationship to be in the early 1950s. This is done by examining the American decision not to pursue a policy in the Iranian oil crisis that would undermine Britain's position, despite at times severe Anglo-American tension. It is concluded that the problems created by the changing balance of forces within the Special Relationship were mitigated in Iran by a combination of consanguinity and, more important, the US need for British help in its policy of global containment. In short, Anglo-American policy-makers perceived sufficient mutual need to persuade them to actively preserve and develop the Special Relationship.