Dr. TONG Ka-Ho, AdrianAdrianDr. TONG Ka-HoLam, Ching YeeChing YeeLam2026-08-032026-08-032026Tong, K. H., & Lam, C. Y. (2026, July 16-19). The power of two: How co-therapy collaboration amplifies ACT outcomes. Association for Contextual Behavioral Science (ACBS) World Conference 2026http://hdl.handle.net/20.500.11861/28396ACT psychoeducation is well-evidenced, yet co-therapy dynamics remain under-researched. Given Wampold’s finding that "therapist factors" drive outcomes as much as techniques, we must ask: how does a co-therapy team amplify effectiveness? This study analyzed the experiences of eight participants in a co-led ACT group. Using reflexive thematic analysis on post-group open-ended questionnaires, we explored the distinct roles and duties of the therapy team. We identified two critical mechanisms: a functional split between "Guidance" and "Facilitation," and a "Co-supportive Environment." Results reveal a sequential process where one therapist builds the theoretical framework, while the other actively observes client reactions. Then, the second therapist fills the gap by providing experiential confrontations, allowing clients to process internal struggles in real-time. This collaborative format helps individuals move beyond mere cognitive acknowledgement to effectively apply the ACT framework to the self, particularly in moving toward a values-driven life. Beyond client outcomes, these findings provide a structured framework for therapist training, offering a clear pedagogical model for mastering effective co-therapy collaboration in ACT intervention.enPresentation