Despite significant investment in many countries, the extent of schools' adoption of obesity prevention policies and practices has not been widely reported. The aims of this article are to describe Australian schools' adoption of healthy eating and physical activity policies and practices over an 8-year period and to determine if their adoption varies according to schools' size, geographic or socio-economic location. Between 2006 and 2013, a representative randomly selected cohort of primary schools (n = 476) in New South Wales, Australia, participated in four telephone interviews. Repeated measures logistic regression analyses using a Generalised Estimating Equation (GEE) framework were undertaken to assess change over time. The prevalence of all four of the healthy eating practices and one physical activity practice significantly increased, while the prevalence of one physical activity practice significantly decreased. The adoption of practices did not differ by school characteristics. Government investment can equitably enhance school adoption of some obesity prevention policies and practices on a jurisdiction-wide basis. Additional and/or different implementation strategies may be required to facilitate greater adoption of physical activity practices. Ongoing monitoring of school adoption of school policies and practices is needed to ensure the intended benefits of government investment are achieved.