The study aimed to investigate the feasibility and effectiveness of face-toface, group-based Compassionate Mind Training (CMT) for undergraduate students. Following a 12-week CMT intervention, a cohort of undergraduate students in the CMT group (n = 45) and their counterparts in the passive control group (n = 21) were asked to fill out assessments before, during, immediately after, and three months following the completion of the intervention. These measures encompassed a range of factors, including self-compassion, negative affect, various forms of positive affect, depression, anxiety, stress, life satisfaction, and dysfunctional attitudes. Compared with the control group, participants belonging to the CMT group showed significant increases in self-compassion and self-warmth, along with decreases in negative affect, self-coldness, dysfunctional attitudes, depression, and stress. However, mediation analyses, when applied within longitudinal models, did not establish the significance of self-compassion, self-coldness, or self-warmth as mediators in the context of the CMT's impact on negative affect and soothing positive affect. The results support the effectiveness of a 12-week, group-based, face-to-face CMT for undergraduate students. Yet, they also cast doubt on selfcompassion as the primary mechanism driving these changes, given the absence of supporting longitudinal evidence.