The purpose of the current study was to examine the mediating effects of emotion regulation on the attachment-psychological distress link among Taiwanese adolescents. A sample of 2124 9th graders from Kaohsiung City, Taiwan was recruited to participate in the study, and the structural equation modeling technique was applied to analyze the data. Findings were as followings. First, boys scored higher than girls on Attachment Avoidance-Mother, Attachment Avoidance-Best Friend, Attachment Anxiety-Father, and School Life Disturbance. Second, there existed significant moderate correlations between attachment toward mother and attachment toward father. Yet, the correlations between attachment toward the best friend and attachment toward parents were weak. Third, two dimensions of attachment toward three different targets were significantly and positively related to adolescents’ self-reported disturbances and depression. Forth, emotion regulation was significantly and negatively associated with disturbances and depression. Fifth, attachment toward parents had not only direct effects on adolescents’ distress but also indirect effects on distress through emotion regulation. Finally, attachment anxiety toward the best friend was directly and indirectly related to distress through emotion regulation. However, attachment avoidance toward the best friend had no significant total effect on distress. Based on these findings, suggestions for future research and implications of interventions on improving adolescent mental health were provided.