It is unclear whether peer victimization in college interacts with genetic vulnerabilities or social support in predicting cortisol secretion. This issue was addressed using a sample of 162 Monozygotic and 237 Dizygotic twin pairs (54% females; 86% Whites, 6% Blacks, 6% Asians, 0.3% Native North Americans). At age 19, participants provided hair for cortisol extraction and reported about victimization in college and support by the mother, father, and best friend. Biometric modeling revealed that environmental influences on cortisol secretion were reduced and genetic influences exacerbated when victimization was high. Moderate to high maternal support mitigated the association between victimization and high cortisol secretion. The findings suggest that victimization in college contributes to physical “wear‐and‐tear”, which may be counteracted by social support.