This study describes the history of the territorial dispute between the United Arab Emirates (UAE) and Iran over Abu Musa, Greater Tunb, and Lesser Tunb, islands located in the strategically important Strait of Hormuz through which 40 percent of the world’s oil and most of the oil from the Gulf region passes. The paper discusses the status of the three islands during the precolonial, British colonial, and post-colonial periods. Of particular note is Great Britain’s role in the Gulf and how it shaped the development of the claims of Iran and the emirates of Sharjah and Ras al-Khaimah over the three disputed islands. The paper also examines the Iranian and UAE legal perspectives concerning the islands in order to get a better understanding of why Iran has consistently refused to submit the case to the International Court of Justice.