Obesity in Europe disproportionately affects people and communities with a lower socioeconomic position (SEP). Effective preventive approaches require consideration of the complex and dynamic interplay between (SEP-specific) biological, sociocultural and environmental risk factors of obesity across the life course. OBCT provides health professionals, researchers, policy makers and the public with knowledge, maps and tools to support sustainable prevention of obesity, with a particular focus on low SEP communities. To achieve this, we quantify the contribution of biological, sociocultural and built environmental risk factors of obesity risks and the interactions in and across various life stages, and translate the resulting knowledge into practical and effective tools for action. Specifically, OBCT will: 1) Advance the current understanding of obesity risks and predictors, and the role of SEP across the life-course; 2) Determine the importance of specific obesity-related behaviours to prevent obesity at key life stage transitions; 3) Develop a holistic obesity risk screener for use by the public at large and by health professionals; 4) Provide country-specific estimates of trends obesity; 5) Provide a digital atlas on the obesogenicity of environments; 6) Characterise obesity-related cardiometabolic risk profiles over gender, age and SEP; 7) Develop tailored lifestyle recommendations; 8) Determine the impact of obesity-related policies on inequality; 9) Provide a decision support dashboard for policy makers; 10) Provide co-developed toolboxes to support implementation of policy recommendations in low-SEP communities. OBCT’s outputs highlight where and in which domains obesity is to be targeted, and empower the research community, policymakers, health professionals and citizens to adapt and implement policies to reduce obesity risk, thereby helping to prevent obesity -particularly in low SEP communities - throughout Europe.