To explore the potential contribution of parents' causal talk to preschooler's emerging scientific literacy and related interests, we observed 153 parent-child dyads playing together in a museum and in the lab. As in previous work, the frequency with which parents referenced causal information in their speech predicted the strength of their children's causal stance. In addition, the frequency with which parents invited their children to explain causal phenomena, but not the frequency with which they provided explanations to their children, was related to children's scientific literacy. These associations held even when controlling for children's parent-reported exposure to science in the home, as well as their general cognitive skills. Although causal conclusions are precluded by the correlational design, this research is consistent with the possibility that parents begin shaping their children's scientific engagement and literacy when they are as young as three years of age.