Objectives The aim of this study was to investigate the efficacy of 2-dimensional (2D) shear wave elastography (SWE) in the diagnosis of acute cystitis (AC) in children. Methods Between June 2019 and March 2020, 126 children with AC and 126 healthy participants were prospectively investigated by 2D SWE and B-mode ultrasound. Elastographic measurements were performed by drawing the contours of the posterior wall of the bladder between the ureter orifices using a free region of interest. The quantitative 2D SWE values of the patients and the healthy group were compared. Results The mean 2D SWE values of the bladder wall were significantly higher in patients with AC compared to the healthy group (P= .001). On B-mode ultrasound imaging, the bladder wall thickness of patients with AC was higher than that in the healthy group (P= .001). On 2D SWE, when the cutoff value used was 9.25 kPa, the sensitivity, specificity, positive predictive value, and negative predictive value were 92.1%, 88.1%, 89.3%, and 92.6%, respectively, whereas when the cutoff value used was 1.72 m/s, the sensitivity, specificity, positive predictive value, and negative predictive value were 90.5%, 88.9%, 89.1%, and 90.7%. There was a statistically significant positive correlation between the 2D SWE values and wall thickness measurements (P < .001). Conclusions Two-dimensional SWE is a noninvasive, fast, and effective imaging method to evaluate the bladder wall in children with AC.