Iran's Constitution, whether before or after revision of 1368, does not express the authority of the legislature to establish councils; nevertheless, Iran's Parliament has established numerous administrative councils. But jurists disagree about this authority of the Parliament; some, referring to the general legislative competence of the Parliament, have confirmed this authority; while some have considered this authority as an interference in the executive branch's authority and against the Constitution. However, the Guardian Council has, subject to certain conditions, confirmed this authority. In this article, in order to identify the legal restrictions of establishing administrative councils by Iran's Parliament, we study the opinions of the Guardian Council in a descriptive analytical manner. According to this, the factors affecting this authority are: binding of the council's authority, content of the council's authority and composition of the council; of course, in most cases, a combination of these factors limits establishing a council. Overall, neither the opinion of the Guardian Council nor of the opponents of this authority of the Parliament can be accepted; the opinion of the Guardian Council regarding authorization to establish a consultative council is acceptable, but Its opinion regarding authorization to establish a binding council (Commissions consisting of ministers) is contrary to Articles 60 and 138 of the Constitution, and Its opinion regarding authorization to establish a recommending council is only acceptable about recommending councils to the Council of Ministers and to each of the ministers, and not about recommending councils to the President and to Commissions consisting of ministers.