Virtual communities (VCs) have emerged as a new form of business model in the electronic business field. Understanding the motivations behind members’ participation is essential for VC organizers. VC participation behavioral intention is a major factor to shape VC participation behavior and it is very important to investigate factors influencing VC behavioral intention. Using the Triandis model of interpersonal behavior, this paper investigated antecedents of behavioral intention to participate in VCs. The results showed that affect, social factors, and perceived consequences are effective in explaining the behavioral intention to participate in VCs. The result also raised the issue of different types of communities’ interaction effects on different strength of relationships.