Given Facebook’s popularity for the maintenance of interpersonal relationships, this investigation examined the extent to which frequency of Facebook communication with a specific friend predicts relational interdependence. The chief goal of the investigation was to extend media multiplexity theory by examining whether attitudes toward (a) online self-disclosure and (b) online social connection moderated this association. Results not only replicated previous findings that multiple media are associated with relational interdependence, but also supported the hypothesized moderation of online communication attitude. Based on these results, the manuscript explores how media multiplexity theory might be extended to account for communicator cognitions about communication media.