Growing interest in mindfulness-based programs (MBPs) has resulted in increased demand for MBP teachers, raising questions around safeguarding teaching standards. Training literature emphasises the need for appropriate training and meditation experience, yet studies into impact of such variables on participant outcomes are scarce, requiring further investigation. This feasibility pilot study hypothesised that participant outcomes would relate to teachers’ mindfulness-based teacher training levels and mindfulness-based teaching and meditation experience. Teachers (n = 9) with different MBP training levels delivering mindfulness-based stress reduction (MBSR) courses to the general public were recruited together with their course participants (n = 31). A teacher survey collected data on their mindfulness-based teacher training, other professional training and relevant experience. Longitudinal evaluations using online questionnaires measured participant mindfulness and well-being before and after MBSR and participant course satisfaction. Course attendees’ gains after the MBSR courses were correlated with teacher training and experience. Gains in well-being and reductions in perceived stress were significantly larger for the participant cohort taught by teachers who had completed an additional year of mindfulness-based teacher training and assessment. No correlation was found between course participants’ outcomes and their teacher’s mindfulness-based teaching and meditation experience. Our results support the hypothesis that higher mindfulness-based teacher training levels are possibly linked to more positive participant outcomes, with implications for training in MBPs. These initial findings highlight the need for further research on mindfulness-based teacher training and course participant outcomes with larger participant samples.