This research examined the relationship of Internet addiction and gaming addiction with school engagement and effects of Internet addiction and gaming addiction on school engagement. The research was conducted with 365 students (140, 38.4%, males; 225, 61.6%, females) studying at an Anatolian high school in Gaziantep province. Personal Information Form, Scale of Internet Usage Addiction, Gaming Addiction Scale for Adolescents and School Engagement Scale for Children and Adolescents (High School Form) were utilized as data collection tools. The data obtained were analyzed with correlation and multiple regression analysis. A weak negative relationship was found between Internet addiction and school engagement. No relationship was found between gaming addiction and school engagement. It was also concluded that Internet addiction is a significant predictor of school engagement and gaming addiction does not predict school engagement significantly.