Abstract. Objective: Increased impulsiveness is a risk factor for health-endangering behavior patterns. Little is known about whether increased impulsiveness is associated with Internet Use Disorder (IUD) and whether individuals with various main activities on the internet differ in their levels of impulsiveness. Methods: In total, we screened 8,230 vocational students for problematic internet use with the Compulsive Internet Use Scale (CIUS). Participants scoring at least 21 points in the CIUS took part in an in-depth diagnostic interview. IUD was assessed according to the criteria of Internet Gaming Disorder (IGD) as suggested in the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Impulsiveness was assessed with the Barratt Impulsiveness Scale (BIS-15). We analyzed the data using binary logistic regression models and nonparametric tests. Results: Participants with IUD ( n = 144) showed increased impulsiveness ( p = .005) compared to those without IUD ( n = 774). Participants with different main activities on the internet did not differ in their levels of impulsiveness. Conclusions: Results indicate that impulsiveness is associated with IUD, independent of the main internet activity. This highlights the necessity to consider patients’ impulsiveness in prevention and therapeutic approaches. Because of the cross-sectional study design, further research with longitudinal study designs is needed.