To evaluate a developmental psychopathology approach for understanding adolescent social anxiety, parent-reported predictors of social anxiety were examined in a nonclinical sample of adolescents. Structured diagnostic interviews were obtained from biological parents of 770 participants. Potential risk factors assessed included child characteristics: negative affect, shyness, separation anxiety disorder, and childhood chronic illness, as well as parent characteristics: major depression, panic disorder, and agoraphobia. Adolescent social anxiety was measured multiple times during high school. Findings indicate stability in social anxiety symptoms across time. Parent-reported, childhood negative affect, shyness, and chronic illness as well as parental panic disorder or agoraphobia were associated with adolescent social anxiety. Interactions were observed between parent-reported childhood shyness and gender and between parent-reported childhood shyness and parent-reported childhood chronic illness in the prediction of social anxiety. Parent-reported childhood shyness was a stronger predictor of adolescent social anxiety in females compared to males. The combined effect of subjects being positive for both parent-reported childhood shyness and parent-reported childhood chronic illness was greater than would be expected based on additive effects. This study provides support for a multifactorial and developmentally informed understanding of adolescent social anxiety.