Out-of-school suspension is associated with adverse educational, justice, health, and welfare outcomes. Little research has focussed on suspensions from primary (elementary) school, despite early exclusions representing high-risk events for poor outcomes. This study aimed to identify early life predictors of primary school suspensions in a sample of 34,855 Australian children using linked education, health, child protection, and justice records for children and their parents. Associations between 26 sociodemographic, pregnancy/birth, child, and parent factors (measured prior to 3rd grade) and subsequent suspensions, issued during the 3rd through 6th grades (ages ~8–11 years), were examined in bivariate and multivariable logistic regressions. In the fully adjusted model, 18 factors were associated with suspension, with the largest effects for male gender, child protection services contacts, and aggressive behaviour. Identification of students at risk of early suspension using multi-sector information available at school entry may assist educators and policymakers to deliver preventative interventions.