BACKGROUND: Although mindfulness benefits are well-established across diverse populations, its impact on primary school children's interpersonal mindfulness, emotional intelligence, and attentional focus remains underexplored. This study evaluated the effectiveness of a four-week mindfulness-based practice (MBP) intervention among primary school students. METHODS: A cluster randomized controlled trial was conducted with 14 classes from Guanghua Elementary School, Taiwan. Classes were randomly assigned to either an intervention group (7 classes, RESULTS: Baseline scores revealed no significant differences between the groups across all measures. After the 4-week intervention, the intervention group showed significant improvements in PR ( CONCLUSION: Overall, the four-week MBP intervention significantly enhanced primary school students' interpersonal mindfulness and attentional focus, with some benefits lasting up to 8 weeks. These findings highlight the importance of tailoring MBP programs to students' developmental stages and gender-specific needs. Future studies should investigate longer interventions and incorporate objective measures to further validate these outcomes.