The current study examined whether adolescents’ attachment representations were associated with differences in emotion regulation during the Adult Attachment Interview (AAI; C. George, N. Kaplan, & M. Main, 1996) and during a mother–adolescent conflict interaction task (Family Interaction Task [FIT]; J. P. Allen et al., 2003). Participants were one hundred and fifty-six 14-year-old adolescents. Dismissing adolescents showed less interbeat interval (IBI) reactivity (indicating less stress) during the AAI than secure adolescents. However, during the FIT, dismissing adolescents showed more IBI reactivity. No differences in physiological reactivity were found between individuals with resolved or unresolved loss or trauma during the AAI or FIT. The results indicate that dismissing adolescents may effectively use a defensive strategy during the AAI but less so in direct conflict interaction with their attachment figure.