Recent reviewers of the group psychotherapy literature have called for the introduction of new constructs that may contribute to a deeper understanding of what it is about process groups that make them effective in eliciting change. To this end, this study investigates the potential of a newly defined and operationalized construct known as self-compassion. Drawing on the writings of various scholars of Buddhism, Neff has theorized that self-compassion consists of three main, mutually influential components: self-kindness (the act of being gentle with oneself in instance of pain or failure); mindfulness (holding painful thoughts and feelings in balanced awareness, without over-identifying with them); and common humanity (the perception of one's experiences as part of the larger human experience). This paper argues that there are strong parallels between each of these three components and existing theory on the mechanisms of change in group psychotherapy. The study was motivated by the belief that preliminary quantitative support for the role of self-compassion in change through groups may highlight the importance of the construct and help orient both group practitioners and group researchers towards a new theoretical lens through which the power of groups may be better understood. 92 subjects were enrolled in the study: 57 in a non-treatment Control condition, and 35 in a Treatment condition. The Control group was comprised of undergraduates from the Educational Psychology Department subject pool at the University of Texas at Austin; the Treatment group was formed by UT undergraduate and graduate students who were enrolled in a process psychotherapy group at the UT Counseling and Mental Health Center. A pre-test/post-test design was employed, with subjects taking identical surveys at baseline (beginning of Fall 2007 semester) and follow-up (end of the same semester). A variety of inferential statistical techniques were utilized, and results indicated that there was a significant relationship between participation in process group psychotherapy and positive mental health outcomes as measured by self-report levels of depression, perceived stress, and happiness; that participation in a therapy group was associated with increased levels of self-compassion; and that as a predictor of mental health outcome in relation to therapy groups, self-compassion was on the whole equivalent to one construct (hope) often cited in the group literature as a powerful therapeutic mechanism, and a more powerful predictor than another (altruism). The overall results offer exciting implications for future research and clinical practice, as they suggest that self-compassion may well serve as an important component of a robust theoretical, organizing lens through which the power of group psychotherapy may be more clearly understood.