Peer victimization is associated with increased risk for mental health problems. These adverse psychological outcomes are linked with altered cognitive and emotional processes and their related neural functioning. In the present study, by using functional magnetic resonance imaging (fMRI), we examined whether peer victimization was associated with heightened neural response to social exclusion. Participants (N = 45; M[subscript age] = 17.7 years, SD = 0.60; 36 women) included three mutually exclusive groups: peer-victimized individuals (targets of bullying), cyberdefenders (defended peers who were being cyberbullied), and controls (not involved as targets or cyberdefenders). All participants underwent an fMRI scan while playing "Cyberball," an experimental paradigm that simulates social exclusion. Peer victimization was associated with increased neural response in the left amygdala, left parahippocampal gyrus, left inferior frontal operculum, and right fusiform gyrus. Understanding the acute neural response to social exclusion in peer-victimized individuals may provide insight into their increased risk for poor mental health.