Background Under the 2013 reforms introduced by the Health and Social Care Act (2012), public health responsibilities in England were transferred from the National Health Service to local authorities (LAs). Ring-fenced grants were introduced to support the new responsibilities. The aim of our study was to test whether the level of expenditure in 2013/14 affected the prevalence of childhood obesity in 2016/17. Methods We used National Child Measurement Programme definitions of childhood obesity and datasets. We used LA revenue returns data to derive three measures of per capita expenditure: childhood obesity (<19); physical activity (<19) and the Children’s 5–19 Public Health Programme. We ran separate negative binomial models for two age groups of children (4–5 year olds; 10–11 year olds) and conducted sensitivity analyses. Results With few exceptions, the level of spend in 2013/14 was not significantly associated with the level of childhood obesity in 2016/17. We identified some positive associations between spend on physical activity and the Children’s Public Health Programme at baseline (2013/14) and the level of childhood obesity in children aged 4–5 in 2016/17, but the effect was not evident in children aged 10–11. In both age groups, LA levels of childhood obesity in 2016/17 were significantly and positively associated with obesity levels in 2013/14. As these four cohorts comprise entirely different pupils, this underlines the importance of local drivers of childhood obesity. Conclusions Higher levels of local expenditure are unlikely to be effective in reducing childhood obesity in the short term.