Parental psychopathology and unfavorable family environment are established risk factors for onset of offspring social phobia (SP), but their associations with the further course, e.g., persistence of the disorder, remain understudied. A community cohort of 1395 adolescents and their parents was followed-up over almost 10 years using the DIA-X/M-CIDI. Parental diagnostic interviews were supplemented by family history data. Parental rearing was retrospectively assessed by the Questionnaire of Recalled Parental Rearing Behavior in offspring, and family functioning by the Family Assessment Device in parents. Persistence measures (proportion of years affected since onset) were derived from diagnostic interviews, using age of onset, age of recency, and course information. Lack of emotional warmth and dysfunctional family functioning characteristics were associated with higher SP persistence, particularly in interaction with parental psychopathology. Predictors for SP persistence differ from those predicting SP onset. Unfavorable family environment alone and in interaction with parental disorders predict higher SP persistence.