Expressed emotion was examined in families of toddlers (N= 101) whose mothers had experienced major depressive disorder occurring since the child's birth, and contrasted with expressed emotion in demographically comparable families (N = 54) with no history of parental mental disorder to elucidate family systems processes as contributors to child functioning. Both mothers and fathers provided Five-Minute Speech Samples on their child, their spouse, and themselves, and completed measures of marital adjustment, trait affect, relationship quality with their own parents in childhood, and child behavior problems. Maternal-expressed emotion criticism regarding child, self, and spouse was higher in the families with depressed mothers; paternal criticism regarding self and spouse also was higher in the depressed families. Mothers and fathers in the depressed group also differed on relational/affective features, exhibiting lower marital satisfaction, higher trait negative affect, and more negative childhood relationship representations, relative to the nondepressed group, and mothers reported more child behavior problems. Mediational models were evaluated separately for the different targets of maternal and paternal criticism and child behavior problems, and findings supported both individual parent and spouse contributions as mediators of the relation between depression group status and expressed criticism and child behavior problems. The findings are discussed in terms of the multiple levels of family system influence on negativity in the emotional environment of toddlers of depressed mothers, developmental risk, and the need for family-level interventions.