Adolescents (N = 107; M = 12.23 years, SD = 1.09 months) participated in a two-part study examining peer victimization, neuroendocrine functioning, and physical health. In phase 1, adolescents completed questionnaires assessing peer victimization and health. They returned for phase 2 which consisted of two sessions. In session 1, adolescents learned to collect salivary cortisol samples; they collected four samples over 2 non-sports school days. In session 2, adolescents completed the Trier Social Stress Test (TSST) in which they prepared and delivered a speech while cortisol was collected. Peer victimization predicted poor health outcomes and a flattened cortisol awakening response (CAR); this CAR was linked with health problems. During the TSST, victims reported more stress and exhibited altered cortisol levels. Higher cortisol immediately after the stressor and lower cortisol 30 min after the stressor were associated with more health problems. This study provides evidence that the relationship between peer victimization and poor physical health may be explained by differences in neuroendocrine functioning. (Contains 4 figures.)