Street connectivity, as a neighbourhood built environmental factor, may affect individual physical activity (PA) and subsequently weight status. However, these associations remain inconclusive. This study aimed to systematically review the association between street connectivity and childhood obesity. A literature search was conducted in the Cochrane Library, PubMed, and Web of Science for articles published before January 1, 2019. All original studies that investigated the association between street connectivity and weight-related behaviours or outcomes among children and adolescents were included. Forty-seven articles were identified, including eight longitudinal and 41 cross-sectional studies conducted in eight countries. The sample size ranged from 88 to 46 813. Street intersection density (SID), measured by Geographic Information Systems in 36 studies and reported in 13 studies, was the main indicator used to represent street connectivity. Forty-four studies examined the association between SID and weight-related behaviours, including overall PA (n = 15), moderate-to-vigorous PA (n = 13), active transport (n = 12), dog walking (n = 1), walking (n = 1), sedentary behaviours (n = 2), and TV viewing (n = 1). Fifteen studies focused on the association between SID and weight-related outcomes. Overall, evidence from this systematic review and meta-analyses suggested a positive association between street connectivity and PA. However, it was difficult to draw a conclusion on the association between street connectivity and BMI. More longitudinal evidence is needed to confirm the causal association between street connectivity and weight status.