ObjectiveTo systematically evaluate the association between vitamin D level and nonalcoholic fatty liver disease (NAFLD) in children and adolescents. MethodsRelated English and Chinese databases, including PubMed, Cochrane Library, Embase, CNKI, CBM, Wanfang Data, and VIP, were searched for studies on the association between vitamin D level and NAFLD in children and adolescents published up to August 2020. Newcastle-Ottawa Scale (NOS) was used to evaluate quality of studies, and RevMan 5.3 software was used for data analysis. ResultsA total of 10 articles were included in the meta-analysis, with 622 patients in the NAFLD group and 1608 in the healthy control group. All 10 articles had an NOS score of ≥6. A pooled analysis of the 10 articles was performed using a random effects model (I2=97%, P＜0.05). The NAFLD group had a significantly lower serum 25(OH) D level than the healthy control group (standardized mean difference=-1.40, 95% confidence interval: -2.07 to -0.72). ConclusionThere is a significant reduction in serum vitamin D level in children and adolescents with NAFLD, which may be associated with the progression and severity of NAFLD.