Objectives: This study examined the effects of a 9-month mindfulness teacher training (MTT) program on mindfulness skills, emotion regulation, and psychological well-being among future mindfulness instructors, compared to a control group. Method: Eighty-seven mindfulness instructors-in-training participated in the MTT program. The control group consisted of age- and gender-matched individuals. Mindfulness skills, emotion regulation, and psychological well-being were assessed at baseline, mid-intervention, and post-intervention using validated measures. Results: In comparison with the control group, participants in the MTT group showed significant improvements in most facets of mindfulness (i.e., observe, describe, non-react, and act with awareness). They also reported decreased rumination, as well as increased personal growth and purpose in life compared to the control group. However, there were no significant differences between the groups in other dimensions of emotion regulation or psychological well-being. Conclusions: This study provides preliminary evidence that mindfulness teacher trainings positively affect mindfulness skills, as well as specific aspects of psychological well-being (personal growth and purpose in life), and emotion regulation (rumination). Future research should investigate the long-term effects of these trainings and how instructors’ well-being relates to their teaching effectiveness. Preregistration: This study is not preregistered.
