Peri-implantitis is an infectious disease that causes inflammation of the tissue surrounding an implant. The aim of this systematic review of the literature is to assess the effect of the use of lasers in the nonsurgical treatment of peri-implantitis in order to estimate its benefits compared with conventional therapies. The review's protocol has been registered on PROSPERO international prospective register. The research strategy was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were as follows: in vivo studies, written in English, measurements of clinical parameters, minimum follow-up at 6 months and with nonsurgical control group, studies about photodynamic therapy, randomized clinical trial, and clinical trial. Electronic (on PubMed, Cochrane, Latin American and Caribbean Health Sciences Literature, and Report Evidence-based Practice Centers databases) and manual searches (in articles' references) were conducted until July 2021. Risk of bias was assessed for each reference thanks to the Cochrane Collaboration's tool. A total of 12 randomized clinical trials, with a high level of evidence, were selected and investigated in this systematic review. A table summarizes data extracted from these articles. It appears that the parameters improve favorably by using lasers, but without any significant difference. In accordance with the analysis of studies, our results show that laser therapy with specific characteristics allows to obtain beneficial therapeutic effects on wound healing in the short and the medium-term concerning the clinical parameters in the nonsurgical treatment of peri-implantitis. Concerning its long-term usefulness, it has yet to be confirmed. However, its benefits remains limited since the results agree that the effects of the laser are similar to those obtained by using conventional therapy.