This study aimed to test a 5-wave sequential mediation model linking maternal mind-mindedness during infancy to children's school readiness in kindergarten through a serial mediation involving child language and effortful control in toddlerhood and the preschool years. Among a sample of 204 mother-child dyads, we assessed maternal mind-mindedness when children were aged 1 year, child expressive vocabulary at age 2, effortful control at ages 3 and 4, and finally cognitive school readiness in kindergarten. The results corroborated the model, suggesting that the prospective association between early mind-mindedness and later cognitive school readiness was entirely mediated by the proposed sequence of mediators, all of which were necessary to account for this longitudinal association. These findings suggest that the potential of parental mind-mindedness to support children's cognitive development may have been underestimated, and that its putative positive influence may take the form of a developmental cascade unfolding during the preschool years and entailing the acquisition of basic skills that serve as building blocks for further learning and development.