Supporting the implementation of school food and nutrition policies (SFNPs) is an international priority to encourage healthier eating among children and youth. Schools are an important intervention setting to promote childhood nutrition, and many jurisdictions have adopted policies, guidelines, and programs to modify the school nutrition environment and promote healthier eating. The purpose of this study was to explore the association between perceived adequacy and capacity for SFNP implementation on food availability and policy adherence in the province of Nova Scotia (NS), Canada, one of the first regions in Canada to launch a comprehensive SFNP. A cross sectional online survey was conducted in 2014-15 to provide a current-state of policy implementation and adherence. Adequacy and capacity for food policy implementation was used to assess policy adherence through the availability of prohibited ‘minimum’ nutrition foods. An exploratory factor analysis was conducted on a selected of available foods and ‘slow’ and ‘quick’ service food composition measures were dichotomized for food availability. Schools with above perceived average adequacy and capacity for policy implementation had more than three times (3.62) greater odds of adhering to a lunch policy, while schools that adhered to a snack and lunch policy had 52% and 82% lower odds of serving quick service foods, respectively. This study identified the need for appropriate adequacy and capacity for policy implementation to ensure policy adherence and improve the school food environment. These findings highlight the potential of SFNPs to have a positive impact on childhood nutrition, but adequately supporting their implementation is critical to ensure their impact.