Wasatiyah or Islamic moderation is a key principle for fostering harmony and tolerance within Indonesia’s multicultural society. As a community-based non-formal Islamic educational institution, Majelis Taklim occupies a strategic position in transmitting and internalizing wasatiyah values among Muslim communities. This study aims to analyze how Majelis Taklim contributes to the internalization and transmission of wasatiyah values through religious learning, social activities, and community engagement. Employing a descriptive-analytical qualitative approach, this study utilizes data obtained through literature review, document analysis, and observation of Majelis Taklim practices in three Indonesian contexts: Batu–Malang, Lubuk Linggau, and Yogyakarta. The findings reveal that Majelis Taklim functions not only as a space for religious knowledge transmission but also as a transformative educational arena where wasatiyah values are embedded through ta‘līm (religious learning), charitable activities, Qur’anic literacy, community service, and social empowerment initiatives. This study contributes to the understanding of non-formal Islamic education by highlighting Majelis Taklim as a grassroots institution capable of strengthening moderate Muslim identity and social cohesion. The findings imply that supporting community-based Islamic educational institutions can serve as an important strategy for sustaining religious moderation and promoting peaceful coexistence in plural societies.