This study aims to provide a well-thought-out insight into the track of political and intellectual changes, which the Arabian Gulf region underwent during the study timeframe (1948-1968), and which had witnessed the emergence of Arab nationalist political organizations that largely affected the political trends and ideologies in the Arabian Gulf region over the subsequent period. The study sheds light on the most prominent Arab issues, which the Arab Nationalist Movement in the Arabian Gulf region both fostered and advocated with popular movement and tangible support. Moreover, the study further clarifies the factors that affected the Arab nationalist organizations in the Arabian Gulf region, and which eventually led them to retreat as political organizations, most evidently in the wake of the Arab defeat in their war against the Zionist enemy in June 1967, and which had effects that extended over the subsequent years. This defeat gave rise to a breakup within the parent Arab Nationalist Movement, thus bringing into light leftist movements that adopted the Marxist ideology. To achieve the study objectives, the researcher adopted the descriptive analytical method, through presenting the historical developments of the Arab Nationalist Movement in the Arabian Gulf region, analyzing the historical data and events, and interpreting them to ultimately reach the conclusions required. In her study, the researched relied on contemporary sources and references, including, among others, Arab and foreign publications, and books, in addition to interviews with persons who lived during the period of study and those who were both part of the events and involved in the Arab Nationalist Movement. The study is divided into an introductory chapter, three chapters and a conclusion. The introductory chapter tackles the political and ideological conditions in the Arabian Gulf region that fostered the Arab nationalism shortly ahead of the emergence of the movement as a political trend. These conditions played a remarkable role in raising the political awareness of the people of the region. Chapter One focuses on the popular movement that turned into a political movement creating a fertile ground for the spread of the Arab nationalism politically, with the emergence of national organizations whose activity emerged in the Arabian Gulf region in the 1950s. Chapter 2 examined the position of Arab nationalist organizations in the Arabian Gulf region towards Arab issues, including: the Arab-Israeli conflict and Syrian Egyptian unity in 1958, as well as the ideological repercussions of these organizations in the Arabian Gulf region. Chapter 3 addresses the decline of Arab Nationalist Movement in the Arabian Gulf region; its causes, forms and repercussions specifically following the Arab defeat in June 1967, which gave rise to deviations and abandonment of Arab nationalism ideology, and to the emergence of left-wing parties that adopted Marxism as an ideology. The study has reached a wide variety of conclusions, most notably: There had been a number of Arab nationalist organizations that engaged in political and ideological activities in the Arabian Gulf region representing the Arab nationalism activity, such as the Arab Nationalist Movement, the Arab Socialist Ba'ath Party, and Nasserism. Nevertheless, the study demonstrated that despite the convergence of ideas and political orientations among the Arab nationalist organizations in the Arabian Gulf region, they did not unite in one Arab nationalist party, due to internal conflicts among those organizations which were not established on an ideological or political basis. The study also explains that the defeat of Arabs in the Arab Israeli war, June 1967 was a turning point in the Arab nationalism ideology, its strategies, and the principles on which it was based since its very inception and rising. This defeat has affected the Arab nationalist organizations in the Arab and Arabian gulf regions, where a number of leftist movements split from the Arab Nationalist Movement adopting the Marxist ideology in their struggle against colonialism and the obsolete Arab regimes. The study showed that despite the decline of the Arab Nationalist Movement in the Arabian Gulf region, it has a marked role in building the ideological and political awareness and in leading the liberation and struggle movements in the region. The Arab Nationalist Movement has had a profound impact on the political experience across the Arabian Gulf region