Background: Job burnout is a major problem among nurses. The three dimensions of job burnout include emotional exhaustion (EE), depersonalization (DP), and low personal accomplishment (PA). Objectives: The aim of this study was to determine the mean of job burnout among nurses in hospitals affiliated to Medical Sciences Universities in Iran. Methods: This was a systematic review and meta‑analysis. An online search was performed in the PubMed, Web of Sciences, Scopus, Google Scholar, Scientific Information Database, Medlib, Iranmedex, Magiran, Civilica, Noormags, and Irandoc databases. The search keywords were “burnout,” “job burnout,” “occupational burnout,” “nurses,” “nursing staff,” and “Iran.” Critical appraisal of eligible studies was performed using the Critical Appraisal Skills Program checklist. The first author’s name, publication year, sample size, and the mean scores and standard error values of the different dimensions of job burnout were extracted from each included study. The random‑effects and the fixed‑effect models were used for the meta‑analysis. The Cochran’s Q test, the I2 index, and the Egger’s regression analysis were used. Results: Nineteen studies with a total sample of 3926 nurses were included in the meta‑analysis. The overall means of the EE, DP, and low PA dimensions of job burnout were 21.19 (95% confidence interval [CI]: 19.28–23.11), 7.85 (95% CI: 6.26–9.43), and 28.89 (95% CI: 27.10–30.67), respectively. The I2 index values of these dimensions were, respectively, 96.6%, 99.4%, and 97.8%, indicating high heterogeneity among the studies. The Egger’s regression analysis showed that there was no evidence of publication bias in the studies (P = 0.08). Conclusion: Job burnout among nurses in Iran is moderate in the EE and the DP dimensions and high in the low PA dimension. Strategies are needed to improve nurses’ work conditions, fulfill their needs, and thereby, reduce their job burnout.