Issue addressed The context of community-based childhood obesity prevention programs can influence the effects of these intervention programs. Leadership readiness for community mobilisation for childhood obesity prevention is one such contextual factor. This study assessed perceived community leadership readiness (PCLR) at two time points in a state-wide, multisite community-based childhood obesity prevention program. Methods PCLR was assessed across 168 suburbs of 20 intervention communities participating in South Australia's Obesity Prevention and Lifestyle (OPAL) program. Using a validated online PCLR tool, four key respondents from each community rated each suburb within their respective community on a nine-point scale for baseline and 2015. Average PCLR and change scores were calculated using the general linear model with suburbs nested in communities. Relationships between demographic variables and change in PCLR were evaluated using multiple regression. Ease of survey use was also assessed. Results Average PCLR increased between baseline (3.51, s.d.≤0.82) and 2015 (5.23, s.d.≤0.89). PCLR rose in 18 of 20 intervention communities. PCLR was inversely associated with suburb population size (r2≤0.03, P≤0.03, β≤-0.25) and positively associated with intervention duration (r2 change≤0.08, P≤0.00, β≤0.29). Only 8% of survey respondents considered the online assessment tool difficult to use. Conclusions PCLR increased over the course of the OPAL intervention. PCLR varied between and within communities. Online assessment of PCLR has utility for multisite program evaluations. So what? Use of a novel, resource-efficient online tool to measure the key contextual factors of PCLR has enabled a better understanding of the success and generalisability of the OPAL program.