There is growing interest in mindfulness-based interventions (MBIs) in the management of multiple physical and mental health issues. Although MBIs utilize a group format, research on how this format impacts teaching and learning mindfulness is lacking. This study aimed to develop a detailed theory of MBI group processes utilizing a grounded theory methodology. This article presents our subsequent model, developed from semistructured interviews conducted with MBI students, teachers, and trainers (N = 12). A core category, the group as a vessel on a shared journey, and three higher-order categories emerged from the data. They illustrate how MBI group processes navigate a characteristic path. Teachers build and steer the group “vessel” in a way that fosters a specific culture and sense of safety. The group is facilitated to share communal experiences that augment learning and enrich mindfulness practice. Limitations and implications for clinicians and researchers are discussed.