Shiites' historically tumultuous life has always been exposed to numerous charges. One of these charges is the claim that the Shiites have received their creed from the Mutazilites. Despite the antiquity of the charge and the fact that Shia scholars have tried to answer it, the charge is still in force. The present study seeks to review the historical roots of such allegations and tries to investigate their causes by referring to some old and modern sources. It also attempts to reply the charges by indicating the distinctions between the Shiite and Mutazilite theological systems and as a result the primacy of Shiite theology over the Mutazilite will be proved. To reject the claim saying the Shiites have obtained their creeds from the Mutazilites, we have mentioned numerous proofs, the titles of which are as follow: A) The refutations offered by the Shiites against the Mutazilites B) The rebukes of the Mutazilites by Shiite Imams and scholars C) The debates of Shiite Imams and scholars with the Mutazilites D) The conversion of some Mutazilites to the Shiism E) Shiism has been charged with "Rafḍ" by the Mutzilites. F)  The difference between Shiite and Mutazilite political position. G) The Shiite belief in infallible Imam, despite the Mutzilites.  H) The fundamental differences of Shiite and Mu'tazilite beliefs. In this research, to answer the question: "why the Shiites are called Mutazilite by some?" four different reasons have been offered which are as follow: A) Shiite and Mutazilite common views in some principles such as the idea of freewill, and rational good and evil. B) Studentship of Zaid bin Ali with Vasil bin 'Ata C) The Mutazilites calling themselves as the Shiite D) The practice of Taqiyyeh by some Shiite scholars Based on what was mentioned above, the differentiation of Shiite and Mutazilite theologies are proved. To prove the primacy of Shiite theology over that of Mutazilite, it is sufficient to refer to some of the remarks of Imam Ali (A). This is because at the time of Imam Ali's martyrdom, Vasil bin 'Ata had not been born yet. By referring to Imam Ali's remarks on justice, man's freewill, impossibility of seeing God in this world and the Hereafter, negation of similarity, and independent intellectual verdicts, which are regarded as similar beliefs in Shiite and Mutazilite theology, it is proved that the Shiites have obtained their theological teachings from their Imams and not from the Mutazilites or anyone else