Purpose: The aim of this study was to evaluate the diagnostic accuracy of 18-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) and positron emission tomography/computed tomography (PET/CT) in imaging primary and metastatic lesions in Ewing sarcoma (ES). Methods: PubMed, Cochrane, Scopus, and Web of Science were searched for relevant studies. Data concerning 18F-FDG-PET/CT diagnostic accuracy were extracted and then analysed using Open Meta-analyst software. Reported diagnostic accuracy outcomes included sensitivity, specificity, negative likelihood ratio (NLR), positive likelihood ratio (PLR), and diagnostic odds ratio. Results: 31 studies with a total of 735 patients were included in this meta-analysis. The sensitivity and specificity of 18F-FDG PET/CT were: 92.6% and 74.1% for total ES lesions, 96.7% and 68.3% for ES primary lesions, 76.1% and 92.4% for lung metastasis, 83.9% and 93.2% for bone metastasis and 89.9% and 92.6% for ES recurrence respectively. Conclusion: 18F-FDG PET/CT is sensitive and accurate in diagnosing, staging, and detecting the recurrence of ES compared to non-PET imaging. It has high specificity for diagnosing recurrence of ES as well as lung and bone metastases.