IntroductionProblematic usage of the internet (PUI) is an umbrella term for a range of uncontrolled, excessive, and potentially harmful online behaviors. Recently, numerous studies have examined the potential of mindfulness programs (MPs) for reducing PUI. We conducted a comprehensive systematic review and meta-analysis in this emerging field.MethodsWe searched eight databases from inception to October 18, 2022, with no language restrictions. We included randomized controlled trials (RCTs) and nonrandomized trials (NRTs). The primary outcome was change in self-reported PUI, the secondary outcome was change in screen time.ResultsOf 3,473 identified records, 19 RCTs and 20 NRTs with a total of 1,549 participants were included. Participation in an MPwas associated with large reductions in PUI in between-group analysis in RCTs (k = 19; g = −1.67; 95% CI −2.15, −1.19) and in within-group pre-post analysis in all studies (k = 35; g = −1.67; 95% CI −1.99, −1.36). Screen time showed a medium reduction in within-group pre-post analysis (k = 10; g = −0.65; 95% CI −0.90, −0.41). The effects for PUI remained significant in a series of sensitivity analyses, such as excluding low quality studies, excluding outliers, adjusting for publication bias, or using follow-up data. Heterogeneity between studies was high and the overall quality of evidence was rated low.Discussion and conclusionsMPs are probably effective in reducing PUI and might be effective in reducing screen time. Shortcomings in the quality of evidence highlight the need for high-quality controlled trials with long-term follow-ups to confirm results.