Background The Optimising Healthy Homes and Neighbourhoods (HHAN) Collaborative Research Project aims to evaluate an intersectoral initiative designed to address the complex health and social needs of families in Sydney facing adverse social determinants of health to reflect HHAN’s holistic approach. Funded by NSW Health and developed by the Sydney Local Health District (SLHD) since 2015, HHAN focuses on breaking cycles of inequity by working with families to address their needs. The initiative particularly serves Aboriginal and Torres Strait Islander families and culturally and linguistically diverse families. Aim & Research Methodology The project assesses HHAN's impact and effectiveness against the quintuple aims of healthcare, using the WHO's integrated people-centred health services (IPCHS) framework. It employs multi-method evaluations, including Indigenous research methods and participatory research, to co-design solutions for optimizing service delivery. Collaborati