Aboriginal and Torres Strait Islander Peoples have sustained complex, healthy and equitable food systems since time immemorial. Embedded in Country, these systems encompass relationships between land, water, sky, people, plants, animals and culture. Colonisation has disrupted traditional food systems and contributed to ongoing challenges in household food security. This project partners with Indigenous communities on Bundjalung Country and in Zenadth Kes (Torres Strait Islands) to co-develop culturally responsive household food security indicators that reflect Indigenous knowledges and lived experiences. Existing measurement tools largely focus on financial access to food and do not capture the broader cultural, environmental and social factors that influence food security from an Indigenous perspective. Using group model building and participatory systems modelling, community members and stakeholders work together to map the complex factors influencing food security in their local contexts. This approach helps identify structural drivers, explore how factors interact, and generate community-led priorities for action. The indicators developed through this process will be grounded in community-defined understandings of food security and wellbeing. They will provide the foundation for an Indigenous Household Food Security Measurement Tool to support the implementation, monitoring and evaluation of local, regional and national food security initiatives and policies.