BackgroundIn Finland, 15–25% of adolescents suffer from mental health problems, and there is increasing concern over stress-related mental health problems. There is initial evidence that mindfulness (MF) interventions might hold some promise. For MF interventions to have the intended effects, it is critical that participants continue practice of MF after the program. To our knowledge, no previous research has examined the extent to which participants take up MF practice, and which motivational aspects of MF interventions predict continued practice of MF (at home) after the conclusion of intervention programs. We aimed to examine 1) what proportion of students report continued practice of MF at home post-intervention, 2) whether perceived norms, self-efficacy, outcome expectancies and intention predict practice at home, and 3) which are the most usual subjectively perceived benefits among those who continue independent practice. Methods This study uses data from an ongoing cluster-randomized trial to test the effectiveness of MF program on student well-being. In the first wave of recruitment, 500 students aged 12–15 years (out of an eventual 2400) were randomly assigned to receive a MF intervention based on the .b program or a control stress management intervention. The MF intervention program consisted of nine weekly MF lessons. We analyzed questionnaires of the intervention arm students (n = 310) at 6 months, i.e., post-intervention. Results 49% of students reported having practiced MF at home after six months. Overall, descriptive norms (i.e. beliefs about what their peers were doing) were the greatest predictor (B = .121, P=.006) of MF practice. Students who continued practice of MF at home six months after the intervention reported the following benefits: better concentration in class (79%); better concentration on hobbies (76%); managing stress better (69%); coping better with difficult emotions (77%); sleeping better (79%); getting better grades in exams (75%); getting along better with friends (85%); and getting along better with family members (84%). Conclusions The results of this substudy can be used in enhancing uptake of MF practice. Future research should aim at examining maintenance of independent MF practice post-intervention with longer follow-ups, and identify best strategies to help students maintain independent practice. messages MF practicing promoted self-reported outcomes attached to improved resilience and emotional balance. School-based MF programs may be a low cost means to promote well-being. Health promotion programs should pay attention to the power of peer behaviour, and take a variety of motivational aspects into account in program design