In the contemporary era, The problem of evil -as one of the most fundamental challenges in the philosophy of religion- has been primarily formulated in three versions: the logical, evidential, and gratuitous (or existential) problems. Adopting a comparative-analytical approach, this article critically examines the responses of two prominent thinkers, Morteza Motahhari and Alvin Plantinga, to these formulations. The research results indicate that Motahhari, by synthesizing the principles of Sadrian philosophy-particularly the fundamentality of existence (asālat al-wujūd), the gradation of existence (tashkīk al-wujūd), and the privative nature of evil-utilizing a theological approach, provides a comprehensive, multi-layered response to all three versions. In confronting the logical and evidential problems, relying on philosophical analyses, he posits evil as a privative entity and a necessary concomitant of the material world characterized by gradations of existence and addressing gratuitous evil, he resorts to a theological explanation by referring to the limitations of human knowledge and the wisdom of the best possible system (niẓām al-aḥsan). In contrast, Plantinga, remaining faithful to the analytical philosophical method and centering his argument on the "Free Will Defense," focuses primarily on refuting the logical incompatibility between the existence of evil and Divine attributes. Consequently, he confines the scope of his philosophical responsibility essentially to the logical problem and moral evil. The primary points of divergence between these two perspectives lie in their methodology (synthetic versus unidimensional), ontological foundations (the fundamentality of existence versus analytical ontology), and the scope of their responses to the three types of evil. Ultimately, this research argues that Motahhari's fluid and systematic approach moves beyond Plantinga's defense, not only in negating the incompatibility but also in providing a philosophical explanation for evils and their justification within “the best possible system”. Furthermore, it offers a theoretical framework for assessing the efficacy of theodicies and defences in addressing all dimensions of the problem of evil.