AIMS: To examine the nurses' burnout and associated risk factors during the COVID-19 pandemic. DESIGN: We followed the Cochrane criteria and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines for this systematic review and meta-analysis. DATA SOURCES: PubMed, Scopus, ProQuest, Cochrane COVID-19 registry, CINAHL and pre-print services (medRχiv and PsyArXiv) were searched from January 1 to November 15, 2020 and we removed duplicates. REVIEW METHODS: We applied a random effect model to estimate pooled effects since the heterogeneity between results was very high. RESULTS: Sixteen studies, including 18,935 nurses met the inclusion criteria. The overall prevalence of emotional exhaustion was 34.1%, of depersonalization was 12.6% and of lack of personal accomplishment was 15.2%. The main risk factors that increased nurses' burnout were the following: younger age, decreased social support, low family and colleagues readiness to cope with COVID-19 outbreak, increased perceived threat of Covid-19, longer working time in quarantine areas, working in a high-risk environment, working in hospitals with inadequate and insufficient material and human resources, increased workload and lower level of specialized training regarding COVID-19. CONCLUSION: Nurses experience high levels of burnout during the COVID-19 pandemic, while several sociodemographic, social and occupational factors affect this burnout. IMPACT: We found that burnout among nurses is a crucial issue during the COVID-19 pandemic. There is an urgent need to prepare nurses to cope better with COVID-19 pandemic. Identification of risk factors for burnout could be a significant weapon giving nurses and health care systems the ability to response in a better way against the following COVID-19 waves in the near future.