Objectives: To systematically assess the efficacy of different non-surgical treatment methods to manage peri-implantitis reported to date in the literature, together with its correlation with time following therapy. Materials and Methods: A systematic literature review was undertaken to identify randomised control trials of the non-surgical management of peri-implantitis published up to November 2019. The search was limited to English language human studies containing follow-up periods of ≥3 months and for sample size of 10 or more patients. A meta-analysis was implemented for the following clinical parameters: Peri-implant pocket depth (PPD), bleeding on probing (BOP), clinical attachment level (CAL), radiographic bone loss (RBL) and mucosal recession (MR). Results: Twelve articles met the inclusion criteria. Two principal treatment modalities were identified; mechanical debridement and laser therapy, with two adjunctive therapies antimicrobial and antiseptic agents. Non-surgical interventions (ultrasonic scalers, Er:YAG laser and powdered air-abrasive devices) showed significant clinical improvement in the short term (<3 months). Clinical benefit was demonstrated with the adjunctive use of antimicrobial agents in the short term but diminished with time. Antiseptic agents alone have no significant effect. Non-surgical therapies applied in these studies failed to arrest mucosal recession, peri-implant bone loss or reduce the counts of viable pathogens in the long term. Conclusion:The evidence demonstrate that the clinical parameters of peri-implantitis, i.e. BOP, PPD and CAL may all be improved by simple mechanical debridement, using either ultrasonic instrumentation or Er: YAG laser therapy; adjunctive antimicrobial and antiseptic therapy. Further randomised control trials in this area are, however, required.