Indonesia is an archipelagic country characterized by diverse cultures, customs, ethnicities, and religions, reflecting the national motto Bhinneka Tunggal Ika (Unity in Diversity). Religious tolerance refers to respecting differences, acknowledging diverse perspectives, and recognizing every citizen’s right to practice their religion and worship freely without coercion. In Bangka Belitung, social harmony is reflected in social and economic interactions, interethnic integration, and a culture of mutual assistance without discrimination. Similar practices can be observed at SMAS Setia Budi Sungailiat, where ethnic and cultural diversity is embraced through the implementation of religious tolerance. This study aims to examine the implementation of religious tolerance at SMAS Setia Budi Sungailiat and analyze the contribution of Islamic Religious Education (IRE) in fostering a culture of tolerance. This study employed a qualitative method with a descriptive approach. The research subjects consisted of the principal, Islamic Religious Education teachers, and students. Data were collected through interviews, observations, and documentation. Primary data were obtained directly from the research subjects, while secondary data were derived from relevant academic books and journals. Data analysis involved three main stages: data reduction, data presentation, and conclusion drawing. The findings indicate that religious tolerance at SMAS Setia Budi Sungailiat is manifested through cooperation, mutual respect, and non-discriminatory behavior toward differences in students’ religious beliefs. Furthermore, Islamic Religious Education contributes significantly to fostering a culture of tolerance by creating a safe and conducive learning environment, encouraging acceptance of diversity and religious freedom, preventing conflict and division, and strengthening harmonious religious life within the school’s pluralistic community.