While existing research has largely concentrated on clinical populations, this study examined the experiences of weight stigma in a typical adolescent sample. We hypothesized that adolescents with higher internalized weight stigma will show increased sympathetic nervous system reactivity and decreased parasympathetic regulation during a peer-to-peer discussion task. Additionally, peer inclusion will moderate the effect of weight stigma on physiological responses, with low peer inclusion intensifying the effects of internalized weight stigma. The study involved 31 adolescents from a magnet school in North Carolina who completed self-report questionnaires to assess internalized weight stigma and peer inclusion. The heart rate variability (HRV) of participants was used to measure sympathetic and parasympathetic activity in terms of modal amplitude and RR intervals. Peer inclusion was found to significantly moderate the relationship between internalized weight stigma and sympathetic reactivity when discussing past experiences of weight bullying/stigmatization. Specifically, adolescents who endorsed high levels of internalized weight stigma and low peer inclusion exhibited heightened sympathetic reactivity in response to the peer discussion task. The findings of this study support the idea that peer inclusion plays a major role in the development of physiological reactivity in response to weight related stressors.