Indonesia is a multicultural nation characterized by diverse ethnicities, religions, cultures, and languages. While this diversity represents a valuable national asset, it also poses potential challenges to social cohesion if not managed appropriately. Islam provides comprehensive principles for promoting unity through fundamental values such as ukhuwah (brotherhood), tasamuh (tolerance), ta'awun (mutual assistance), justice (al-'adl), and deliberation (shura). This study aims to examine Islamic values in fostering unity within Indonesia's pluralistic society and to explore their implications for strengthening social harmony. The research employed a qualitative approach using a library research method. Data were collected from primary sources, including the Qur'an, Hadith, and classical as well as contemporary Islamic literature, complemented by secondary sources such as scholarly journal articles, academic books, and government policy documents. The collected data were analyzed using qualitative content analysis through data identification, categorization, interpretation, and conclusion drawing. The findings indicate that Islamic teachings provide a comprehensive framework for nurturing social cohesion by promoting religious moderation, tolerance, justice, and respect for diversity. Furthermore, Islamic Religious Education plays a strategic role in cultivating inclusive, moderate, and responsible citizens capable of living harmoniously within a multicultural society. The study also highlights that strengthening religious moderation, multicultural education, and digital literacy constitutes an effective strategy for addressing contemporary challenges, including intolerance, radicalism, misinformation, and social polarization. Therefore, the contextual implementation of Islamic values through education, dialogue, exemplary leadership, and responsible digital engagement is essential for reinforcing national unity and preserving the integrity of the Republic of Indonesia