Today, due to the increasing interest in hybrid education environments and technology integration into the course, mobile devices have started to be used in face-to-face classroom lessons. In addition to the many advantages of using mobile devices in the classroom, it also leads to some undesirable situations. One is related to developing students' habits of playing digital games during the lesson. This research aimed to determine the relationship between students' digital game addiction and selfishness, one of the individual differences, on their academic motivation and classroom engagement. Participants were 860 high school students in grades 9 to 12. The research used a correlational design. The result of a path analysis revealed that selfishness was related to digital game addiction; as the level of selfishness of the students' increased, the probability of digital game addiction also increased. Also, digital game addiction was associated with academic motivation and was not related to classroom engagement, such that, as academic motivation levels of the students increased, the classroom engagement levels also increased. Recommendations for what can be done to increase the students' academic motivation and classroom engagement are discussed.