Cesarean section (CS) delivery is a common procedure, and its incidence is increasing globally. To compare single-layer (SL) with double-layer (DL) uterine closure techniques after cesarean section in terms of ultrasonographic findings and rate of CS complications. PubMed, Scopus, Web of Science, and Cochrane Library were searched for relevant randomized clinical trials (RCTs). Retrieved articles were screened, and relevant studies were included in a meta-analysis. Continuous data were pooled as mean difference (MD) with 95% confidence interval (CI), and dichotomous data were pooled as relative risk (RR) and 95% CI. Analysis was conducted using RevMan software (Version 5.4). Eighteen RCTs were included in our study. Pooled results favored DL uterine closure in terms of residual myometrial thickness (MD = -1.15; 95% CI -1.69, -0.60; P < 0.0001) and dysmenorrhea (RR = 1.36; 95% CI 1.02, 1.81; P = 0.04), while SL closure had shorter operation time than DL closure (MD = -2.25; 95% CI -3.29, -1.21; P < 0.00001). Both techniques had similar results in terms of uterine dehiscence or rupture (RR = 1.88; 95% CI 0.63, 5.62; P = 0.26), healing ratio (MD = -5.00; 95% CI -12.40, 2.39; P = 0.18), maternal infectious morbidity (RR = 0.94; 95% CI 0.66, 1.34; P = 0.72), hospital stay (MD = -0.12; 95% CI -0.30, 0.06; P = 0.18), and readmission rate (RR = 0.95; 95% CI 0.64, 1.40; P = 0.78). Double-layer uterine closure shows more residual myometrial thickness and lower incidence of dysmenorrhea than single-layer uterine closure of cesarean section scar. But single-layer closure has the advantage of the shorter operation time. Both methods have comparable blood loss amount, healing ratio, hospital stay duration, maternal infection risk, readmission rate, and uterine dehiscence or rupture risk.