Studies have demonstrated the association between parenting style and children's academic achievement, but the specific mechanisms underlying this relationship remain unclear. The development of skills that lay the foundation for academic success might be found in early parent–child interactions that foster language competence. Early negative parenting beliefs, characterised by a lack of reciprocal parent–child interactions may put a child's developing language at risk, which then compromises a child's subsequent academic success. The present study investigated this idea by using longitudinal data and structural equation modelling on a sample of 1364 children at 1 month and 36 months and in kindergarten and grade 1 (National Institute of Child Health and Human Development study of Early Child Care and Youth Development). Authoritarian beliefs were measured at 1 month and in grade 1. Language competence was measured at 36 months and in kindergarten, and academic achievement in kindergarten and grade 1. We found that children's language functioning at 36 months fully mediates the association between early negative parenting beliefs and children's subsequent academic achievement.