AimThis systematic review and meta‐analysis aimed to analyze studies that examined the relationship between psychological capital and burnout in registered nurses.Background and introductionRegistered nurses are subject to high rates of burnout, with negative consequences on health, well‐being, and quality of care. Psychological capital could be an important element in preventing or reducing this condition.MethodsThis research is based on the Joanna Briggs Institute Guidelines and Preferred Reporting Items for systematic reviews and meta‐analysis. A total of 180 studies on psychological capital and burnout were retrieved from Web of Science, Scopus, PubMed, Medline, and PsycINFO. The articles were written in English, Spanish, French, and Portuguese. Then, 23 studies were included in several meta‐analyses (random‐effects models) performed with the R statistical program.ResultsAnalysis of the 23 studies revealed that psychological capital and burnout are significantly correlated. The Psychological Capital Questionnaire (PCQ) and the Maslach Burnout Inventory (MBI) were the most used scales to measure psychological capital and burnout, respectively. The meta‐analyses showed an inverse correlation between psychological capital and burnout (r = −0.44, 95% CI [−0.51, −0.36], n = 6092), and emotional exhaustion (r = −0.32, 95% CI [−0.42, −0.21], n = 3349).ConclusionThis review provides evidence of the negative relationship between psychological capital and burnout in registered nurses. Therefore, enhancing psychological capital is an effective strategy to prevent and reduce burnout in nurses.Implications for nursing and health policyPsychological capital is a personal resource open to development over time and susceptible to interventions aimed at promoting optimism, efficacy, hope, and resilience. In that sense, training aimed at improving psychological capital, as a protective mechanism to prevent and reduce burnout and emotional exhaustion, should be considered together with organizational measures to promote nurses' health and well‐being.