God’s Will is one of the most important discussions whose theological and philosophical interpretations are different from each other, though, regarding interpretation of “God’s Will”, some of the theologians have been inclined to philosophical thoughts. In the early Imamieh theologians’ beliefs, with emphasis on the concepts of the Ahlul - Bayt’s hadiths, will was one of the stages of God’s Act and it was meant “determined to Providence”; however, along with Mu’tazila of Baghdad, Baghdad School interpreted this term as “divine action” or “order to action”, though considering innate nature for will and interpreting it as “knowledge to expediency in actions” had some advocates, too. After Baghdad’s School and during the history of Imamieh theology, interpretation of will was influenced by philosophical thoughts and ultimately, in Hilla School, will was interpreted as an innate issue or stimulus i.e. “knowledge to expediency and goodness in actions”. This study intends to investigate the whatness of will from philosophers and theologians’ viewpoint and its evolution during Medieval, especially in theology of Baghdad and Hilla schools and having a comparative evaluation on these viewpoints, it attempts to find their relation with an approach to narrations.