Video games are especially popular among adolescents and young adults as a form of entertainment and the amount of time spent playing video games has increased rapidly. The main objective of this study is to assess the effect of video games on cognitive functions in adolescents. An exploratory, cross-sectional study was employed to investigate cognitive function in adolescent video game players. Cognitive functions, including memory, attention, and executive functions, were evaluated in 46 adolescents who had been playing video games regularly for at least 1 h per day, 5 days per week, for at least a year, and 31 adolescents (who played video games <5 h per week) using cognitive function assessment tests. Other data, such as demographics, medical information, video game types, and time spent playing video games were collected by questionnaires. No significant difference was detected between the groups in terms of age, gender, IQ levels, and sociodemographic variables. Our findings show that visual memory results were slightly better in the playing group. Moreover, in the group that plays video games regularly, the increase in daily time spent playing games significantly increased the total error value in the Stroop Test and total interference value in California Verbal Learning Test-Children's Version test. We also found that more time is spent on online games compared with traditional games. In this study, we emphasize the pathological and uncontrolled consumption of video games and the possible consequences of time spent playing games. Our findings indicate the need for more extensive research. Future research should address the various implications of video game play, especially between the potentially positive and negative effects of video games.