Children in food-insecure households may be at risk of poor health, developmental or behavioural problems. This study investigated the associations between food insecurity, potential determinants and health and developmental outcomes among children. Data on household food security, socio-demographic characteristics and children's weight, health and behaviour were collected from households with children aged 3-17 years in socioeconomically disadvantaged suburbs by mail survey using proxy-parental reports (185 households). Data were analysed using logistic regression. Approximately one-in-three households (34%) were food insecure. Low household income was associated with an increased risk of food insecurity [odds ratio (OR), 16.20; 95% confidence interval (CI), 3.52-74.47]. Children with a parent born outside of Australia were less likely to experience food insecurity (OR, 0.42; 95% CI, 0.19-0.93). Children in food-insecure households were more likely to miss days from school or activities (OR, 3.52; 95% CI, 1.46-8.54) and were more likely to have borderline or atypical emotional symptoms (OR, 2.44; 95% CI, 1.11-5.38) or behavioural difficulties (OR, 2.35; 95% CI, 1.04-5.33). Food insecurity may be prevalent among socioeconomically disadvantaged households with children. The potential developmental consequences of food insecurity during childhood may result in serious adverse health and social implications.