Therapeutically Applied Role-Playing Games provides a comprehensive approach to implementing therapeutically applied role-playing game (TA-RPG) groups for mental health practitioners. When facilitated by a trained professional, TA-RPGs are a powerful tool for insight, growth, and change for individuals and communities. The Game to Grow Method of Therapeutically Applied Role-Playing Games is a transdiagnostic, transtheoretical, group intervention developed over a decade of practice using Dungeons & Dragons and other popular tabletop role-playing game systems, as well as leveraging therapeutic factors from acceptance and commitment therapy, marriage and family therapy, drama therapy, and interpersonal process groups. TA-RPGs are conceptualized as a gaming system layered on top of established intervention techniques. They can accommodate a multitude of game systems and align with theoretical mechanisms for change found across therapeutic orientations. This work serves as a comprehensive training manual for TA-RPGs, providing a valuable resource for mental health professionals interested in incorporating TA-RPGs into their practice.