Introduction: Statins are effective therapeutic agents for the treatment of cardiovascular diseases. Their favorable effects on various aspects of the oral health including positive effects on bone metabolism and their pleiotropic effects such as anti-inflammatory properties made this group of drugs as a current area of interest in the field of orthodontic relapse. Our review systematically investigates and evaluates the quality of the available evidence regarding the effects of Statins on relapse after orthodontic treatment. Materials and Methods: A comprehensive search of MEDLINE, ISI web of science, EMBASE, Scopus, and Cochrane databases for studies measuring the effects of Statins on the amount of relapse after orthodontic treatment up until February 2020 was performed. To assess risk of bias and study quality while in our review SYRCLE and COMARADES tools were used. The protocol of this review was registered via (crd.york.ac.uk/Prospero) with the ID CRD42020170389. Results: Seven animal trials were finally included in this review. According to the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) Tool, all of the included studies had at least one domain in high risk of bias. Four studies reported decrease in the orthodontic relapse after statins administration, but 3 studies showed no statistically significant changes. Conclusions: Based upon the animal studies and methodological inconsistencies among the included studies, conclusive confirmation regarding the effect of Statins on relapse after orthodontic treatment remains debatable