The opportunities and challenges related to Internet use continue to grow, as well as the social concern around problematic Internet use (PIU), online risky behaviors, and the intensive use of Internet, mainly among adolescents. The aim of this study was to conduct a general screening of PIU in a large sample of school-based adolescents in Spain (n = 40,955), providing updated prevalence data of PIU and different online risky practices, as well as rates of Internet and social network use. Differences between problematic and nonproblematic users were explored in terms of demographics, parental control, and motivations for using. The association between PIU and the involvement in other online risky behaviors was also analyzed, as well as the role of intensive use. The findings show that the global prevalence of PIU among Spanish adolescents is 16.3 percent although this is higher among females, those in their late teens, intensive users, and those without parental control. Logistic regression confirmed that both PIU and intensive use are risk factors for being involved in any online risky behavior. A tentative explanation could be that there is a common deficit of personal and social skills underlying PIU, intensive use, and most online risky practices. From our perspective, value-based education and life skills training are the best way to reach responsible and sensible use of Internet among adolescents. Parents, schools, institutions, and adolescents themselves are called upon to actively engage in facing this problem.