Internet addiction, although not recognized by the WHO or the APA, is a serious and problematic pathology. This meta-analysis shows that the incidence of Internet addiction in adults was high in recent years (2017–2020). The effect size returned according to the random effects model is Z = 24.63; SE = 0.205; p = .001. In addition, high heterogeneity is evident in the research addressing this topic (Q = 1240.719, df = 36, p < .001; I2 = 97.09%). On the other hand, the Eggers test indicated an absence of publication bias. The sample consisted of 30 studies with k = 37 samples from Europe, Asia, America and Oceania. The total sample was constituted by 21,378 participants (51.22% male, 48.78% women; Mean age = 23.55 years). The statistical analyses of meta-regression and model comparison show a complex problem at the international level, explained by age and sex, and apparently also by geographical area. The results of the systematic review show the increase of internet addiction in the new generations, with other variables playing a relevant role, such as: Increase of individualism, lower sociability and enculturation. We conclude highlighting the need to address this problem from a public health approach.