Background: The internet is extremely popular nowadays; it has not only positive but also negative effects, especially on the physical and mental health. The similarities between substance abuse and behavioral dependence have given rise to the concept of behavioral addiction. Objectives: To determine the prevalence of internet addiction disorder (IAD) among Benha University students and find out the presence of psychiatric disorders and emotional dysregulation in relation to IAD. Subjects and Methods: A comparative observational cross-sectional study was conducted on 400 students from Benha University, who were chosen by a random technique convenient to our study. A semistructured interview; clinical psychiatric assessment; psychometric tests such as the Young Internet Addiction Test, SCID I, and SCID-II; and test for affect regulation scale (Trait Meta Mood Scale) were performed for all participants. Results: Internet addiction was common among Benha University students (77.5%). Overall, 10.0% were diagnosed as having avoidant personality disorder and 10.0% with histrionic personality (both were statistically significant). Moreover, 6.1% had obsessive personality, 1.3% had passive aggression personality, 1.0% had paranoid personality, 1.0% had dependent personality, 6.7% had borderline personality, and 7.1% had antisocial personality. Overall, 53.2% of students with IAD had suicidal ideas, whereas 61.3% had insomnia (both were statistically significant). There was a statistically significant difference between the studied groups regarding major depressive disorder, substance use disorders (54.8%), and generalized anxiety disorder (54.8%). Conclusions: There was a high prevalence of IAD among Benha University students (77.5%). Substance use disorders, major depressive disorder, generalized anxiety disorder, insomnia disorder, and suicidality were statistically significantly higher among students with IAD, in addition to avoidant and histrionic personality disorders.