The transition to school is a sensitive developmental period for young children. Although children born very/extremely preterm have increased risk of health and developmental concerns, predictors of their school readiness and adjustment remain largely unexamined. Parents of very/extremely preterm-born children (aged 3–7 years; pre-transition n = 114, post-transition n = 112) completed an online survey assessing their perceptions of children’s school readiness (pre-transition) or adjustment (post-transition), support needs, child behaviour, parent distress, and parent confidence. Poorer school readiness and adjustment and greater needs for support correlated with child health/developmental condition/s; hyperactivity, peer problems, conduct problems, emotional symptoms, and less prosocial behaviour; and lower parent confidence. Using hierarchical linear regression, parent confidence emerged as the strongest common predictor of school readiness (pre-transition) and school adjustment (post-transition), followed by low hyperactivity, high parent education (tertiary), and no diagnosed child health/developmental condition/s. Results will be used to identify families needing support and develop tailored support strategies.