Children with additional health and developmental needs (AHDN) are at risk of experiencing disparities in their early school progress that are unnecessary and preventable. Australian estimates suggest that 4% of children have established AHDN formally recognized within the education system. Many more – around 18% or 49,873 starting school each year – experience emerging AHDN, where the child’s condition is milder, undiagnosed, or lies within diagnostic grey areas. Despite their number and the malleability of their school pathways, this latter group of children with ‘grey area’ difficulties are often ignored in research and policy, which instead tend to focus on children experiencing moderate to severe disability. Children with emerging AHDN are likely to have lower academic achievement than their peers and to have poorer wellbeing and adjustment outcomes. Health conditions can influence academic outcomes through their impact on body functions and structures (e.g. neurological functioning); activities of daily living (e.g. self-care); social participation (e.g. peer acceptance); and educational participation (e.g. school attendance). Surrounding risk and protective factors at the child, family, and service system level are also likely to influence outcomes. Many of these intervening factors are modifiable and so it is likely that children’s outcomes are readily ameliorated given appropriate support or intervention. We therefore need data on children with emerging AHDN in Australia to advocate for these children to receive the support they require to thrive at school and reach their full educational potential. This issue is particularly relevant given the Victorian Government is currently reviewing its approach to supporting children with additional needs through the Program for Students with Disabilities. This paper will use the Australian Early Development Census (AEDC) to inform this policy discussion. The AEDC is exceptional in the near-total national coverage of school entrants (2012: 96.5%, N=289,973). It provides teacher-reported information on five key domains of early child development, including physical health and wellbeing, social competence, emotional maturity, language and cognitive skills, and communication skills and general knowledge. Importantly, it also has the rare benefit of containing a validated measure of both emerging and established AHDN. Results from the AEDC will be presented examining the characteristics, support needs, and academic pathways of children with emerging AHDN. The implications for school based responses to supporting children with AHDN will be discussed, including for approaches to funding services to support children’s healthy development.