Adolescents commonly experience social anxiety, an impairing set of fears of unfamiliar social situations. Yet, we know little about factors implicated in how adolescents maintain these concerns. One factor robustly implicated in adolescents’ externalizing behavior involves parental awareness of adolescents’ whereabouts and activities (i.e., parental monitoring). Not only do we know little about the links between parental monitoring and social anxiety, but also parents and adolescents often provide discrepant reports about such monitoring. Prior work indicates that these discrepant reports facilitate understanding adolescent externalizing behaviors. I explored whether these reporting discrepancies also predict adolescents’ social anxiety, within a controlled laboratory paradigm that measured adolescents’ reactions to interacting with unfamiliar peers. The interaction between low levels of adolescent-reported parental monitoring and high levels of parent-reported parental monitoring related to increased adolescent anxiety during these interactions. These findings inform how to use parental monitoring assessments when assessing and treating adolescent social anxiety.