Source credibility has been defined as the attitude toward a source of communication held at a given time by a receiver. Ancient rhetoric tied credibility to the notion of ethos, while new rhetoric would highlight the rhetor’s need to create identification. Through persuasion theory, modern social psychology has used social scientific research to assess and expand on the list of credibility factors. Still, much of the ancient theory is still considered valid.

This entry first sketches the views of source credibility held within rhetorical theory before discussing the contributions from persuasion research. The entry also discusses the cultural turn toward authenticity, how digital media affect source credibility, and the implications of source credibility for corporate reputation.