The primary aim of this study was to examine whether individual differences in cool and hot executive functions (EF) were associated with children's transition to school, in terms of both academic performance and classroom behaviour. Children between 5- and 7-years-of-age (N = 90) completed performance based assessments of cool and hot EF as well as verbal ability. Teachers reported on children's reading and numeracy performance, learning-related behaviours, hyperactivity, and aggression. Results revealed that EF, in particular working memory, was associated with reading and numeracy performance and that this relation was mediated by learning-related behaviours. EF was not associated with hyperactive or aggressive behaviour. The findings strengthen the evidence base for the importance of EF in early academic performance and underscore its potential to be a beneficial part of early education curriculum and a target for early intervention for successful transition to school.