Aim and design: This systematic review aimed to estimate the prevalence of online natural health products (NHPs) purchases among consumers. Data Sources: Four databases (PubMed, Science Direct, Scopus and Web of Sciences) were searched for articles published up to July 1, 2021. Review Method: Studies included were those reporting the prevalence of online NHPs purchases, those excluded were case reports, commentaries, letters, editorials, review articles, theses and non-English studies. The risk of bias of selected studies was assessed using the Joanna Briggs Institute’s checklist, and the pooled prevalence of online NHPs purchases was generated using the random-effect model. Results: A total of 30 studies were included in the meta-analysis, representing a total of 40,535 respondents. The pooled prevalence of online NHPs purchases was estimated at 7.60% (95% CI: 5.49, 10.01). Prevalence was higher in studies conducted in recent years, among physically active populations and when sports nutrition was included within the scope of NHPs. More than half of the selected studies have a moderate risk of bias, and considerable heterogeneity was observed across the selected studies. Conclusion and Impact: Online purchases of NHPs are not common among consumers, but they have become more common in recent years. A wide range of NHPs were investigated across studies, which may have contributed to the considerable heterogeneity reported in this review. It is suggested that future studies investigating online NHPs purchases consider reporting individual prevalence statistics specific to each NHP type, to facilitate meaningful comparisons between studies.