The lack of access to sidewalks is a barrier for physical activity (PA) and may be a risk factor for childhood obesity. However, previous studies reported mixed findings and the association between sidewalk accessibility and childhood obesity remains unclear. This study systematically examined the evidence on the association between sidewalk accessibility and childhood obesity. PubMed, Cochrane Library, and Web of Science were searched for relevant articles (published before 1 January 2019) that reported on the association between neighborhood sidewalk access and weight‐related behaviors and outcomes in children. Seventeen studies conducted in five countries were included. Ten studies used objective measure of access to sidewalks, seven studies measured children's height and weight, and seven studies objectively measured the PA or sedentary behaviors. Ten studies reported on the association of better access to sidewalks with increased PA (β ranging from 0.032 to 2.159; p < 0.05), reduced sedentary behaviors (β ranging from −0.19 to −0.14; p < 0.05), lower body mass index (BMI) (β ranging from −0.261 to −0.144; p < 0.001), or obesity risks (OR ranging from 1.02 to 1.32; p < 0.05); while the remaining seven studies did not report a desirable obesity–sidewalk association. Our findings support the hypothesis that higher sidewalk accessibility is associated with higher PA levels, lower BMI, and obesity risks. Efforts in building healthy environments, including health‐promoting city planning, can help minimize the growing obesity epidemic and promote public health.