Sex offenders demonstrate heightened levels of negative emotions, traumatic experiences, mental health issues, and emotion disregulation. This study presents a qualitative analysis of interviews with sex offenders concerning helpful experiences in experiential group psychotherapy. Experiential group psychotherapy aims to increase emotional awareness, emotional expression, and reflection on emotions. The data were thematically coded according to Yalom's therapeutic factors for group psychotherapy. The results indicate that Cohesion is reported to be most helpful: when clients trust their peers and feel respected by therapists, emotional engagement in treatment is achieved. Clients report being more capable of focusing on and tolerating their own emotions, which also influences the way they relate to other people (Interpersonal learning). Experiences related to Universality, Instillation of hope, Altruism, and Existential learning were also mentioned as helpful in the treatment.Keywords: group psychotherapy, experiential therapy, therapeutic factor, sex offender, child molester, client perspective, emotion THERAPEUTIC FACTORS FOR SEX OFFENDERS 3 "Simply speaking your mind, from the depths of your soul": therapeutic factors in experiential group psychotherapy for sex offendersThe first and foremost aim of sex offender therapy is the prevention of recidivism. However, we know from general therapy literature that therapeutic success depends on active engagement by both parties, a will to change in the client, the therapist's skill to get around resistances and an approach based on the client's needs and strengths (Levenson, Prescott, & D'Amora, 2010;Serran, Fernandez, Marshall, & Mann, 2003;Wampold, 2001). In the field of sex offender treatment, the responsivity principle purports that clients can only respond to treatment if the service delivery matches their abilities to learn from it (Andrews, Bonta, & Wormith, 2011). For this reason, it has been noted that the tendency to overmanualize offender treatment reduces the therapist's ability to respond to the client's unique features and therefore decreases the effectiveness (Marshall & Burton, 2010).The issue of responsivity is a crucial but underexplored area compared to research on risk factors or criminogenic needs. The existing literature confirms the importance of the way in which treatment is delivered to the patient. Jennings & Sawyer (2003) described the importance of group process and the facilitative techniques that will enhance the effectiveness. Strategies for increasing engagement include using a positive, empathic approach that encourages and supports client ownership of change, which may decrease the need for self-protective strategies such as denial (Kear-Colwell & Pollock, 1997). Beech and Fordham (1997) found that therapeutic atmosphere had an important influence on treatment change. Successful groups were cohesive, had effective leadership, produced a sense of group responsibility, encouraged expression of feelings, and instilled hope in mem...