Cyber victimization is an important research area, yet little is known about aversive peer experiences on social networking sites (SNSs), which are used extensively by youth and host complex social exchanges. Across samples of adolescents (n = 216) and young adults (n = 214), we developed the Social Networking‐Peer Experiences Questionnaire (SN‐PEQ) and examined its psychometric properties, distinctiveness from traditional peer victimization measures, and associations with internalized distress. The SN‐PEQ demonstrated strong factorial invariance and a single‐factor structure that was distinct from other forms of peer victimization. Negative SNS experiences were associated with youths' symptoms of social anxiety and depression, even when controlling for traditional peer victimization. Findings highlight the importance of examining the effects of aversive peer experiences that occur via social media.