The Handbook of Video Games and Mental Health offers the first comprehensive, interdisciplinary account of how video games can function as tools for psychological insight, intervention, and community-building. At a time when mental health systems struggle with engagement, accessibility, and scalability, this volume examines whether the games already embedded in the daily lives of billions can help bridge the gap between need and care. With helpful, research-based insights for game designers, clinicians, researchers, and theorists, this handbook is an essential resource for advancing video games as mental health tools. Bringing together leading researchers, clinicians, and designers, the handbook integrates theory, empirical research, and real-world applications across a wide range of mental health domains, including anxiety, depression, trauma, neurodivergence, community engagement, and cultural preservation. It introduces mechanism-based frameworks that map game mechanics onto evidence-based therapeutic processes such as exposure, cognitive reframing, emotional regulation, and social connection. The volume is organized into three parts. Foundational chapters establish conceptual and methodological frameworks for understanding games as psychological systems, while the second part contains application-focused chapters that examine how these frameworks translate into interventions across clinical populations. The final section addresses community dynamics, ethical challenges, and future directions, emphasizing issues such as inclusivity, safety, cultural context, and implementation at scale. This book is an essential guide for anyone interested in the future of mental health care, digital interventions, and interactive technologies.