This chapter provides a comprehensive examination of psychological perspectives on gaming disorder and compulsive gaming behavior, beginning with the conceptualization and symptomatology that distinguish the disorder from normative gaming habits. We outline the diagnostic criteria established by the DSM-5 and ICD-11, analyzing how these frameworks have evolved with advancements in clinical understanding and shifting societal attitudes toward gaming. The discussion extends to the adverse impacts of gaming disorder on both mental and physical health, emphasizing associated psychiatric issues such as depression and obsessive-compulsive disorder, as well as broader health concerns such as sleep disturbances and musculoskeletal problems. Furthermore, we identify personal and social risk factors that heighten susceptibility to gaming disorder, including cognitive factors like poor impulse control and socio-environmental influences like family cohesion. Finally, we review a range of treatment approaches, from individual-focused cognitive-behavioral therapy and family-based interventions to emerging digital mindfulness and gamification therapies, evaluating their efficacy and applicability. By synthesizing current research and clinical practices, this chapter offers valuable insights for scholars and mental health professionals seeking to understand and effectively manage gaming disorders across diverse populations.