To determine whether clinical supervision (CS) of health professionals improves patient safety.Databases MEDLINE, PsychINFO, CINAHL, EMBASE and AMED were searched from earliest date available. Additional studies were identified by searching of reference lists and citation tracking.Two reviewers independently applied inclusion and exclusion criteria. Thirty-two studies across three health professions [medicine (n = 29), nursing (n = 2) and paramedicine (n = 1)] were selected.The quality of each study was rated using the Medical Education Research Study Quality Instrument. Risk ratios (RR) were calculated for patient safety outcomes of mortality, complications, adverse events, reoperation following initial surgery, conversion to more invasive surgery and readmission to hospital.Results of meta-analyses provided low-quality evidence that supervision of medical professionals reduced the risk of mortality (RR 0.76, 95% CI 0.60-0.95, I(2) = 76%) and supervision of medical professionals and paramedics reduced the risk of complications (RR 0.69, 95% CI 0.53-0.89, I(2) = 76%). Due to a high level of statistical heterogeneity, sub-group analyses were performed. Sub-group analyses provided moderate-quality evidence that direct supervision of surgery significantly reduced the risk of mortality (RR 0.68, 95% CI 0.50-0.93, I(2) = 33%) and direct supervision of medical professionals conducting non-surgical invasive procedures significantly reduced the risk of complications (RR 0.33, 95% CI 0.24-0.46, I(2) = 0%).CS was associated with safer surgery and other invasive procedures for medical practitioners. There was a lack of evidence about the relationship between CS and safer patient care for non-medical health professionals.