LAUSR

Abstract Prosocial and health protective behaviors are critical to contain the COVID‐19 pandemic, yet adolescents have been difficult to engage. Attachment security promotes adolescents’ capacities to navigate stress, and influences prosocial and health behaviors. Drawing on a diverse sample of 202 adolescents (48% female; 47.5% Latinx) this study evaluated relations among attachment, mental health, and prosocial and health protective responses to the COVID‐19 pandemic. Attachment security (age 12) predicted adolescents’ (age 15) COVID‐19 prosocial (f 2 = .201) and health protective behaviors (f 2 = .274) during the pandemic via smaller‐than‐expected increases in mental health symptoms above pre‐pandemic levels (age 14). Findings highlight the importance of attachment for supporting adolescents’ mental health responses to life stressors and promoting prosocial and health protective behaviors.