The year 1996 is considered a milestone in modern Omani political history, as it witnessed the first written constitutional organization in the Sultanate, with the issuance of the basic system of the ?constitution? of the state 26 years after Sultan Qaboos-mayAllah have mercy on him- came to power. The Sultanate moved from a onechamber system to a parliamentary dual system. This thesis came to clarify the historical development of the Parliamentary Councils in the Sultanate, and its composition, and competencies and evaluate its performance, especially after the issuance of Royal Decree No. 99/2011 amending some provisions of the statute that represents an important point at the level of legislative and oversight powers of the Oman Council. In this Thesis, we have reached the conclusion of set of results, the most prominent of which is that the constitutional legislator has built the relationship between the executive authority and the Council of Oman on basis of separation, based on balance and cooperation. However, this separation is only apparent in form, as it was found that the appointed State Council does not have any political jurisdiction oversight, as the appointed State Council?s competence was restricted to the legislative and financial field only. The Thesis also reached a number of recommendations, as indicated in the conclusion.