This study examines the relations between the First Saudi State and Oman during the period from 1215H/ 1800AD to 1233H/ 1818AD. The study takes the year 1215H/1800 as established by the researcher as the starting point for the beginning of relations between the First Saudi State and Oman. The last year of the above-mentioned period, 1233H/ 1818 which ends that period, represents the defeat of the First Saudi State by the Ottoman Wali, Mohammed Ali Pasha. In spite of the fact that the relations at that time were characterized by hostilities and military conflicts, the two countries had constant intellectual contacts. The researcher has managed to find that a flow of intellectual contact was going on between the two at the time. The researcher states that this finding has never been mentioned in all previous studies that he has checked. In addition, the researcher highlights the role of Britain in the Arabian Gulf Peninsula at that time through its presence and rule in India. The researcher employs the analytic procedures of the inductive approach while examining stories about the historic episodes of the two countries, the differing views as revealed in various texts and sources he has referred to. The study comprises three chapters. Chapter one presents the history of the founding and establishment of the Busaeedi State and the First Saudi State. Furthermore, the researcher touches on the history of Oman coast area and the prominent political powers at that time. This is followed by presentation on the First Saudi State's move towards the Eastern parts of the Arabian Peninsula coupled with the very beginning of the intellectual contacts between the two countries. Chapter two deals with the military conflicts between the two, and chapter three presents the factors behind the success of the First Saudi State's campaigns on Oman and the impact of the collapse of the Dir'iyyah on the First Saudi State and the political circumstances in Oman. At the end, the author concludes the following: 1. The emergence and establishment of intellectual contacts between the two states. 2. The Royal family dispute for power in Oman between 1804-1806AD was one major reason behind the success of the Saudi influence on some areas in Oman. . 3. In addition, the following factors were behind the Saudi campaigns success. First and foremost of which is the tribal conflicts, divide, and the role of some prominent Omani tribes who made an alliance with the Saudi side.