Background: No systematic review or meta-analysis has yet been performed to examine the global prevalence of nomophobia by population, by instrument. Thus, this review was performed to estimate the prevalence of nomophobia by severity. Methods: American Psychological Association PsycINFO, Cochrane, Cumulative Index to Nursing and Allied Health Literature (CINAHL), EBSCOhost, EMBASE, MEDLINE, ProQuest Medical, ScienceDirect, Scopus, and Web of Science from inception of each respective database to second week of January 2021 were used. There was no language restriction. The random-effect meta-analysis model was used with the DerSimonian and Laird methodology was used for computation. Results: Twenty papers, involving 12,462 participants from ten countries, were evaluated for meta-analysis. The prevalence of moderate to severe nomophobia is 70.76% [95% CI 62.62%; 77.75%]. The prevalence of severe nomophobia is 20.81% [95% CI 15.45%; 27.43%]. University students appeared to be the highest group affected with a prevalence of severe nomophobia 25.46% [95% CI 18.49%; 33.98%]. Meta-regressions of severe nomophobia showed that age and sex were not a successful predictor of severe nomophobia β = −0.9732, p = 0.2672 and β = −0.9732, p = 0.4986. Conclusions: The prevalence of severe nomophobia is approximately 21% in the general adult population. University students appeared to be the most impacted by the disorder.