God's self-knowledge serves as the foundation for major philosophical and mystical theories within the mystical and philosophical schools of Ibn ‘Arabī and Mullā Ṣadrā. Both thinkers, employing relatively similar approaches, have sought to explicate divine self-knowledge. This paper, initially, through the analysis of the data and secondly by utilizing the comparative approach, aims to examine the conceptual and content correspondence of the views of these two mystics and philosophers on the topic of self-knowledge. This paper aims to examine the conceptual and substantial correspondence of the views of these two mystics and philosophers on the topic of self-knowledge, initially through data analysis within the philosophical and mystical traditions, and subsequently by utilizing a comparative approach. The findings reveal the profound influence of the worldview of Islamic mysticism on Sadrian philosophy on the issue of the levels of divine knowledge. In some of Mullā Ṣadrā’s later works, explicit distinctions between the states of the ultimate Unseen (Ghayb al-Ghayūb) and the first and second determinations (al-ta'ayyun al-awwal and al-ta'ayyun al-thānī) are defended. Moreover, Sadrian philosophical principles, such as the rule of “the simple reality is all things” (basīṭ al-ḥaqīqa kull al-ashyāʾ), are employed to support these distinctions. In the Sadrian perspective, this rule is oriented toward the second determination. While the author acknowledges the presence of seemingly conflicting passages in Mullā Ṣadrā’s works, it is clarified that these passages are in line with most other phrases that are employed to explicate the levels of knowledge within the lordly domain.