Obesity is one of the most pressing global public health concerns in the 21st century. Systems approaches are increasingly applied to tackle the complex problem of childhood obesity prevention and there is a growing interest in the creation of upscaling guidelines for applying systems approaches. The aims of this research proposal are: 1) investigate how context shapes local obesogenic systems, 2) determine the role of context in facilitating and hindering the adoption of systems approaches against childhood obesity, and 3) establish recommendations to scale up systems approaches against childhood obesity. Two case studies from the European GrowH! project will be analysed to understand the obesogenic system driving childhood obesity in two communities to determine the role of local context in shaping these systems. A scoping review will be conducted to evaluate published causal loop diagrams portraying the complex mechanisms that drive childhood obesity to determine shared and context-specific obesogenic system characteristics. Next, a scoping review will be conducted to analyse published systems frameworks guiding the application of systems-based approaches against childhood obesity, to identify key principles for the successful application of this novel strategy. Finally, the results from the three studies will be further substantiated through a Delphi study to identify key guiding principles for policy makers to upscale systems approaches against childhood obesity.