Multicultural education has the potential to foster social harmony while supporting academic achievement in diverse school settings. Despite its relevance, little is known about its implementation and impact in Indonesian vocational high schools (SMK), where students come from varied cultural, religious, and socio-economic backgrounds. This qualitative study employed a case study design to examine how multicultural education is practiced in one state vocational school. Data were collected through semi-structured interviews with five informants (teachers, a student, and a vice principal), participant observation, and document analysis. A thematic analysis was applied, and it was supported by methodological and source triangulation to ensure validity. Findings reveal that multicultural education is enacted through curriculum content integration, culture-based extracurricular activities, and inclusive school policies. These strategies cultivate a classroom climate that values diversity, enhances student confidence, and motivates active learning. Moreover, structured cross-cultural interactions reduce prejudice and strengthen social relationships among students. Teachers observed higher participation, particularly from students of minority backgrounds, while administrators reported reduced intergroup conflicts and stronger collaboration across cultural lines. The study concludes that multicultural education plays a dual role in academic and social development. When implemented contextually in vocational schools, it can promote student engagement and foster social cohesion. However, given the study’s limited scope and reliance on qualitative perceptions, broader research with mixed-method approaches is recommended to better capture the impact on measurable academic outcomes.