Objectives <p>Childhood is a key developmental period for acquiring metacognition and meta-emotion skills, which are crucial for lifelong learning and social functioning. Although both skills involve monitoring mental states, their specific roles in relation to trait mindfulness are not well understood. Clarifying how metacognition and meta-emotion interact with mindfulness is essential for understanding their impact on children's psycho-social development. This study, therefore, examined the reciprocal associations between mindfulness, metacognition, and meta-emotion using a three-wave cross-lag model in a sample of Chinese elementary school students.</p> Method <p>This longitudinal study followed 541 Chinese children (249 males; mean age = 10.56 years, <i>SD</i> = 0.49) across three time points, each separated by 5-month intervals. Participants completed questionnaires assessing mindfulness, metacognition, and meta-emotion. Cross-lagged panel modeling was used to analyze the longitudinal relationships among these variables.</p> Results <p>After controlling for gender and age, results indicated that metacognition significantly predicted meta-emotion over time, and vice versa. Mindfulness significantly predicted meta-emotion over time, but the reverse was not observed. These significant relationships were observed only between Time 1 and Time 2, but not between Time 2 and Time 3. No significant association was found between mindfulness and metacognition.</p> Conclusions <p>While metacognition and meta-emotion exhibited reciprocal associative relationships, mindfulness was associated only with meta-emotion, not with metacognition, suggesting these skills may develop independently. Future research should focus on mindfulness-based interventions, and explore their effects on metacognition and meta-emotion.</p> Preregistration <p>This study is not preregistered.</p>