Introduction Early childhood experiences have a lifelong impact on a child's future. Social and environmental experiences and interactions have a profound relational effect on children's physical and mental health which transfers agency to parents, caregivers and duty-bearers to care for the child's welfare. In the Australian context early child development indices have been in decline in some communities. Hence, there is a sense of urgency to reverse these trends from an integrated perspective. A multisector, multi component program of interventions named A Good Start in Life is proposed and is being tested in the Australian Capital Territory across suburbs with high levels of early childhood development disadvantage. The aim of this study is to evaluate the outcomes and processes related to targeted interventions, designed to integrate child and family services within the local district and embed allied health programs into early childhood education, care services and playgroups. Methods and analysis The Good Start in Life study will use a quasi-experimental design (with a matched control geographical area) consisting of a combination of interventions that will build multisectoral collaboration across education, health and social services that connect and support families with children from birth to 5 years. The control area will be matched on demographic characteristics and early child development outcomes and trends over the pre-intervention period. Evaluation data will be collected at baseline, and then on an annual basis for a further three years. A mixed methods approach will be used to evaluate delivery processes: quantitative (checklists, questionnaires) and qualitative methods (observations, focus groups and key stakeholder interviews). Effectiveness of the programme will be evaluated by comparing early child development outcomes between the comparator areas from the Australian Early Development Census in 2024. The primary focus will be on reducing the number of children who are developmentally vulnerable on at least one early development index (EDI). Separate tests will be conducted for significant differences in the percentage of children at risk in each of the five individual EDI domains. These domains are physical health and wellbeing, social competence, emotional maturity, language and cognitive skills, and communication and general knowledge.