This paper studies Facebook users’ learning-based attitude formation and the relationship between member attitude and self-disclosure. Through the theoretical lens of learning theories, we recognize the key antecedents to member attitude toward a social networking as stemming from classical conditioning, operant conditioning, and social learning-related factors. In addition, we explore the underlying process through which member attitude affects self-disclosure extent and theorize the mediating role of site usage rate on the relationship between attitude and self-disclosure extent. Analysis of 822 survey data results provides strong support for the role of learning theories in explaining Facebook members’ attitude development. The results also confirm a significant, partial mediating effect of site usage rate. A series of post-hoc analyses on gender difference further reveal that attitude formation mechanisms remain constant between male and female Facebook users; gender difference exists on the association between attitude and self-disclosure extent and the association between site usage rate and self-disclosure extent; and the mediating effect of site usage rate exists in male user group only. Our research, therefore, contributes to the literature on social networking sites, as well as providing behavioral analysis useful to the service providers of these sites.