In studies concerning modern Islamic civilization, a critical subject involves examining internal diversities within the Islamic civilizational environment; among the most significant issues related to such diversities are political opponents within the political system. Political opponents may be analyzed from various perspectives, one of the most crucial being their citizenship rights—a modern concept that can also be identified within the foundations of Islamic law (sharīʿah). This research primarily investigates the status of political opponents in Islam's political system from the perspective of the Holy Quran, focusing on their citizenship rights and its impact on the Islamic civilization-building process. Although citizenship rights initially appear as a modern concept stemming from liberal discourse, reflection upon Quranic teachings and Islamic legal principles reveals conceptual foundations of these rights even toward political opponents. Utilizing a qualitative method with an interpretive-analytical approach, this study selectively examines verses of the Holy Quran concerning opposition, tolerance (tasāmuḥ), patience (ṣabr), rationality (ʿaqlāniyyat), and justice (ʿadālah) toward others, analyzing them through authoritative Islamic commentaries (tafāsīr) and contemporary theories on civil society and religious governance. Findings demonstrate that while acknowledging societal diversity and opposition, the Holy Quran not only prohibits suppressing opponents but obligates the Islamic state to exercise patience, restraint, dialogue, and engagement with them; numerous verses emphasize principles such as human dignity (karāmah insāniyyah), invitation through wisdom (ḥikmah), and ethical treatment of opponents. Thus, upholding opponents' rights constitutes not a temporary expediency but a fundamental principle arising from divine justice (ʿadl ilāhī) in Islam's political order. Such an approach not only prevents social divergence but contributes to realizing modern Islamic civilization by strengthening participation, enhancing public trust, and promoting dialogue. Therefore, safeguarding opponents' citizenship rights represents an intellectual and structural necessity in the Islamic civilization-building process.