Internet gaming and social media usage (SMU), particularly among children and teenagers, have witnessed a remarkable surge over the past decade. However, it remains uncertain whether this widespread usage has a positive or negative impact. The primary objective of this systematic review was to investigate the diverse effects of excessive video game playing and extensive SMU, both favorable and detrimental, on the psychological and mental well-being of children and adolescents. To assess the influence of internet gaming disorder (IGD) and disordered SMU on the mental health of children aged 6-12 years and adolescents aged 13-18 years, we conducted a systematic review of 20 studies on the subject. These studies utilized a substantial sample size of 48,652 participants, encompassing online and in-person questionnaires administered to children, teenagers, and their parents in educational institutions, healthcare facilities, and online platforms. Our findings suggest that multiple factors contribute to the intricate relationship between SMU, video game playing, and mental health outcomes. The majority of research indicates that excessive gaming or SMU among children and teenagers leads to adverse consequences on their mental well-being. Furthermore, certain studies have even reported fatal consequences, while others have identified a worsening of preexisting mental health issues. A few studies have explored the potential positive impacts of SMU and gaming on individuals and society at large. In light of this, we have concluded that it is inappropriate to categorize internet gaming and SMU as solely beneficial or detrimental without considering the broader context and the interplay of various factors.