Abstract Purpose This review aimed to evaluate the therapeutic effects of Reiki therapy on quality of life. Methods The review followed standard scientific journal practices and a systematic search of PubMed, Web of Science, Embase, Scopus, and the Cochrane Library, with a literature cutoff of September 2024, was conducted to identify relevant studies. Inclusion criteria comprised articles published in English, randomized controlled trials (RCT), Reiki therapy as the independent variable, diverse patient populations, and outcome measures focusing on quality of life improvement. Results The review involved 661 participants aged 14 years and above, showing a significant enhancement in quality of life post-Reiki therapy (SMD = 0.28, 95% CI 0.01 ~ 0.56, P = 0.043). The subgroup analysis showed that Reiki therapy interventions with a frequency of ≥ 8 sessions and a duration of ≥ 60 min and acute interventions of ≤ 20 min were most effective in improving quality of life. Conclusions The existing meta-analysis and systematic review suggested that Reiki therapy positively impacted quality of life. Therefore, it was recommended that patients with cancer, surgical patients, chronic illnesses, and the general population receive acute Reiki therapy sessions (≤ 20 min) or Reiki therapy with sufficient frequency (≥ 8 sessions) and duration (≥ 60 min) to enhance their quality of life. Systematic review registration Systematic review registration: PROSPERO CRD 42023483961.