This study examines the relation between the longitudinal course of maternal depression during the child's early life and children's psychophysiology and behavior at age 6.5 years. One hundred fifty-nine children of depressed and nondepressed mothers were followed from infancy through age 6.5 years. Growth mixture modeling was used to identify classes of depressed mothers based on the longitudinal course of the mother's depression. School-aged children of chronically depressed mothers were found to have elevated externalizing behavior problems, decreased social competence, reduced frontal brain activation (EEG power), and higher respiratory sinus arrhythmia reactivity. Children of mothers with decreasing and stable mild depression were found to have increased hyperactivity and attention problems compared to children of nondepressed mothers. Contextual risk factors were found to mediate the relation between maternal depression and child behavioral outcomes.