The knowledge of the Imam and its scope have been subjects of discussion and inquiry since the concept of Imamate emerged in the Islamic world. This topic has been particularly significant among Shiite scholars, approached from various perspectives, leading to diverse and sometimes conflicting theories. This article, using a descriptive-analytical method and by explicating and analyzing the existential dimensions of the Imams of the Ahl al-Bayt (peace be upon them) and the totality of evidence related to their knowledge and its scope, strengthens the theory that the Imam, in terms of spiritual existence, possesses complete knowledge, encompassing all knowable matters—except the essence of God's nature. However, the Imam's knowledge in the material realm depends on their connection to their luminous and spiritual existence and their utilization of it. In the case of complete connection, their knowledge is complete; otherwise, it is limited to the extent of the Imam's will and intention. Nevertheless, in matters such as religious rulings and knowledge essential to the spiritual and ongoing life of the Imam and the community, their knowledge is consistently and permanently complete.