The association between neighbourhood walkability and children's independent mobility using an ecological approach is relatively unexplored. In 2007, 1480 10- to 12-year-old children (and 1314 parents) attending low and high walkable schools across Perth, Western Australia, completed surveys. Objective built environment, social-cultural and individual-level factors were explored. High neighbourhood walkability predicted girls' independent mobility. However, girls and boys were more likely to be independently mobile if they and their parents were confident that they could travel independently. Providing safe, walkable neighbourhoods – particularly for girls – combined with strategies to improve children's skills to safely navigate their neighbourhood may increase independent mobility.