The present study examined references to cognitive states and emotions in narratives produced by mothers and preschoolers (aged 3 or 5 years) in Polish and American families. Participants were 32 mother-child dyads from Poland and 32 mother-child dyads from the United States. The two samples were matched with regard to child age, child gender, maternal age, and maternal education. The mother-child dyads were asked to tell three personal narratives. The co-constructed narratives were coded for mother and child references to cognitive states and emotions. Polish mothers were found to include significantly more references to cognitive states in their narratives than American mothers. Results also revealed significant correlations between mothers’ and children’s references to cognitive states across both samples. Related to child development, 5-year-olds produced significantly more tokens in the narratives than 3-year-olds. This study shows that mothers’ use of cognitive state terms in shared narratives with their young children differs across two Western cultural contexts. The results of this study are discussed with regard to two themes in developmental psycholinguistics: relations between maternal and child language use, and cross-cultural variation.