Using a longitudinal sample of children, this study examined the relation between maternal Expressed Emotion (EE) and mother-child attachment disorganization at age 6 years. A nonclinical sample of 33 children (at ages 12 months and 18 months) from Berlin, Germany participated with their mothers in Ainsworth's Strange Situation. Thirty-two children were again observed with their mothers at age 6 years in a standard laboratory attachment observation. At the time of the 6-year assessment, maternal EE was assessed based on a Five-Minute Speech Sample. Mothers also completed the Life Events Questionnaire, a measure of family stress, and the Present State Examination, a measure of maternal depression. Maternal Expressed Emotion was significantly linked to mother-child attachment security at age 6 years. Further analyses revealed that High EE was most closely linked to the disorganized attachment pattern at age 6 years, an at-risk attachment pattern that has been associated with intrusive and hostile maternal behavior. The relationship was upheld when other relevant variables, including infant attachment disorganization and a measure of perceived family stress, were simultaneously considered. The study provides independent validation of Expressed Emotion as a measure of relationship quality in early childhood. It also provides a basis for the further investigation of the nature of the relation between maternal Expressed Emotion and attachment disorganization.