OBJECTIVES: The utility of ultrasound for diagnosing diverticulitis, especially in high-risk cases with complicated diverticulitis, remains debated. This study aimed to provide contemporary quantitative data synthesis of the diagnostic accuracy of ultrasound in patients with suspected diverticulitis. METHODS: Scopus, PubMed, Google Scholar, and CENTRAL were searched from January 1st,1990 to September 15th, 2023, for potentially relevant articles. Selected studies evaluated and reported estimates of diagnostic accuracy of ultrasound for the diagnosis of acute diverticulitis using CT as the gold standard. Subgroup analyses were conducted for simple versus complicated diverticulitis, and for point-of-care ultrasound (POCUS) versus radiology-performed ultrasound (RADUS). Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. Diagnostic odds ratios, sensitivity, specificity, likelihood ratio, and area under the receiver operating characteristic curve with 95 % confidence intervals (CI) were reported. RESULTS: A total of 12 diagnostic studies (n = 2056 patients) were identified. Ultrasound showed a sensitivity of 92.5 % (95 % CI 86.9 %-95.8 %) and specificity of 87.7 % (95 % CI 75.7 %-94.2 %) for detecting acute diverticulitis. The positive likelihood ratio (LR+) was 8.28 (95 % CI 4.74-14.45) and negative likelihood ratio (LR-) was 0.08 (95 % CI 0.05-0.15). For complicated diverticulitis ultrasound had a sensitivity of 58.3 % (95 % CI 46.1 %-69.8 %) and specificity of 98.2 % (95 % CI 96.4-99.2). The LR+ was 31.86 (95 % CI 15.61-65.06) and LR- was -0.42 (95 % CI 0.32-0.56)). Subgroup analysis showed POCUS had 94.1 % (95 % CI 91.4 %-95.9 %) sensitivity and 89.8 % (95 % CI 77.6 %-95.7 %) specificity, while RADUS had 83.2 % (95 % CI 68.3 %-91.9 %) sensitivity and 88.7 % (95 % CI 76.1 %-95.1 %) specificity for detecting acute diverticulitis. CONCLUSIONS: Ultrasound had high accuracy for diagnosing acute diverticulitis with greater sensitivity when performed by emergency physicians and surgeons at the bedside. For complicated diverticulitis, the overall sensitivity was lower, while the specificity was higher.