Purpose: This study examined how complexity of maternal epistemological beliefs predicted mothers' and children's talk about the mind. Method: Twenty-eight mothers of 5- to 10-year-olds completed a measure of receptive vocabulary, and mothers and children participated in a storytelling task specifically designed to elicit talk about the mind. Their use of mental state terms to encode pragmatic functions and mothers' epistemologies were assessed and compared. Results: Maternal mental state talk and amount of talk increased with epistemological complexity. With the number of utterances held constant, mothers with simple, dualistic perspectives of knowledge used mental states more often to direct interaction; mothers with more complex epistemologies used mental states more often to encourage child reflection. Mothers with the less complex perspective underperformed on the receptive vocabulary measure in comparison to others. Children's amount of talk and use of a variety of mental state terms also increased with maternal epistemological complexity. The amount of talk and mental state terms produced by mothers and children frequently persisted after the effects of maternal receptive vocabulary were removed. Conclusions: Maternal epistemologies predict several qualities of mothers' and children's mental state talk that may contribute to children's developing theory of mind.