This study examines Plotinus’s ontological system—as one of the most coherent frameworks in Neoplatonism—and investigates its capacity to inspire Muslim philosophers in articulating fundamental philosophical principles. The main research problem is how the hierarchy of being in Plotinus’s thought grounds widely used principles in Islamic philosophy and how this connection can be methodologically explained. The research aims to analyze the structure of the levels of being in Plotinus’s thought and demonstrate its relation to principles in Islamic philosophy. Employing a descriptive–analytical approach based on library sources—especially Plotinus’s primary works and authoritative contemporary scholarship—the findings indicate that Plotinus’s ontological system rests on emanation from the One and the gradual descent of being through Intellect, Soul, Nature, and Matter. This structure provided a foundation for formulating several philosophical principles in Islamic philosophy, such as the Principle of the One (Qāʿidat al-Wāḥid), Emanation (Fayḍ), the Simple Reality (Basīṭ al-Ḥaqīqa), the Impossibility of Infinite Regress (Imtināʿ al-Tasalsul), the Unity of Intellect, Knower, and Known (Ittiḥād al-ʿĀqil wa al-Maʿqūl), the Unity of Being (Waḥdat al-Wujūd), and the Gradation of Being (Tashkīk al-Wujūd). Ultimately, while Muslim philosophers reconstructed these principles within distinct theological frameworks, the Plotinian system played an inspiring and foundational role in their conceptual formation