Utilizing a random probability sample of Canadian residents aged 15–64 (n = 8116), this study assessed gender differences in the onset of social phobia and the moderating influence of gender on indicators of childhood family adversity hypothesized to increase the risk of developing the disorder. Results revealed statistically significant “gender by family adversity” interactions that varied by disorder sub-type. Among males, absence of a parent or other adult close confidant during childhood was associated with an elevated risk of developing social phobia (all diagnosed cases and the non-generalized sub-type). Risk factors unique to females included parental conflict while growing up (all diagnosed cases), childhood physical abuse by a father figure (generalized sub-type), and maternal mania (non-generalized sub-type). Results highlight the importance of distinguishing between social phobia sub-types in gender-based research as well as the use of family adversity measures that capture the parenting behaviors and mental health status of both parents.