The present study examines the longitudinal and differential impact of different dimensions of the early years home learning environment (HLE) on children's reading and mathematical competencies in secondary school, while taking early developmental outcomes and HLE during secondary school into account. During the preschool years, 554 three-year-old children were tested and have been followed up to the age of 13. The results show that book exposure and the quality of verbal interactions regarding mathematics both predicted mathematical outcomes in secondary school and that those effects were mediated through early language and arithmetic skills. Reading outcomes in secondary school were not directly predicted by early HLE but indirectly via early language and literacy skills. Path models reveal that the different dimensions of the early HLE were differentially associated with preschoolers' early competencies. All effects remained significant when including the concurrent HLE during secondary school which predicted reading outcomes directly.