Self-forgiveness is a relatively new construct in the positive psychology literature. Many researchers posit that self-forgiveness promotes well-being, psychologically and relationally, but others worry it might serve as a moral disengagement strategy that can harm individuals and relationships. In the present chapter, I conducted a qualitative review of 65 published empirical studies exploring associations of self-forgiveness with mental health and relational well-being. In order to address discrepancies in the literature, the review highlights more sophisticated studies and explores the differences that emerge when the construct of self-forgiveness is assessed as a state as opposed to a trait. In particular, measurement concerns are identified, specifically noting the lack of studies in the field that assess well-being while considering the two-part definition of self-forgiveness. Implications for future research and practice are discussed. The present study examined the effect of an adapted self-forgiveness intervention. Drawing on clinical considerations, I posit that existing interventions may be a poor fit for individuals, such as maladaptive perfectionists, who are prone to difficulties with self-evaluation and self- condemnation. I incorporated techniques from cognitive behavioral therapy to facilitate more realistic self-appraisal and tested the revised intervention. Utilizing an RCT framework, participants who completed the intervention showed significantly higher levels in a variety of self-forgiveness outcomes. Additionally, individuals high in maladaptive perfectionism showed worse baseline levels but a greater response to the intervention. Implications for future research and practice are discussed.