The aim of the study was to expand the current knowledge base on problematic video gaming and ADHD with four questions: (1) Are there differences in the length of video gaming between boys with ADHD and typically developing boys? (2) Are there differences in problematic video gaming between boys with ADHD and typically developing boys? (3) What are the predictors of problematic video gaming? (4) Does problematic video gaming affect academic performance while controlling for the effect of inattention and hyperactivity/impulsivity symptoms? Symptoms of inattention, hyperactivity/impulsivity scale (SNAP IV), the Problematic Video Game Scale, and the Video Game Patterns Questionnaire were administered to 127 parents of elementary school boys in Croatia, 57 of whom were parents of boys with a clinical ADHD diagnosis and 70 of whom were parents of typically developing boys. The results show that there are no differences in length of play and problematic video gaming between ADHD and typically developing boys. A hierarchical regression analysis showed that age, inattention symptoms, and length of play are predictors of problematic video gaming. Inattention symptoms and age are significant predictors of academic achievement whereas it seems that hyperactivity and impulsivity symptoms are not predictors of problematic video gaming and academic achievement in boys.