The aim of this study is to focus on stress reactivity as a moderator of the transmission of depression from mothers to adolescents through emotional insecurity. One hundred mother-adolescent dyads living in the Northeast of the United States were examined, with adolescents between the ages of 13 to 17. Data was collected in the home through surveys, a mother-adolescent interaction task and physiological measures from the adolescent to examine stress response. Results suggested that adolescents’ emotional insecurity mediated the relationship between maternal and adolescent depressive symptoms. Findings also provided some support that adolescents who evidenced a higher stress response to the conflict interaction task appeared more vulnerable to the transmission of depression through emotional insecurity. These findings can help in the understanding the intergenerational transmission of depressive symptoms from mothers to adolescents through important factors such as quality of attachment and stress reactivity.