Research has shown that children of depressed mothers are at risk for problems in a variety of developmental domains; however, little is known about the effects of maternal depression on children's emerging understanding of false beliefs. In this study, 3 false belief tasks were administered to 5-year-old children whose mothers had either met criteria for major depressive disorder within the first 20 months of the child's life (n = 91) or had never been depressed (n = 50). Significant difficulties in performance were found among the children of depressed mothers, especially those whose mothers had experienced early and recent recurrent depressive disorder. Regardless of diagnostic status, children whose mothers exhibited negativity during problem-solving tasks administered at an earlier developmental period also were less likely to demonstrate false belief understanding. These effects remained even after child verbal ability was controlled. (Contains 1 footnote, 5 tables, and 1 figure.)