In this study, we examined the potential mediating role of instructor credibility in the relationship of instructor self-disclosure and nonverbal immediacy to student incivility in the college classroom. Four hundred thirty-eight students completed online questionnaires regarding the instructor of the class they attended prior to the one in which the study was administered. Dimensions of instructor credibility mediated the relationship of instructor self-disclosure valence, instructor disclosure relevance, and nonverbal immediacy, with student incivility. In addition, the dimension of competence mediated the relationship of instructor communicative behaviors with the other two dimensions of credibility. The amount of instructor self-disclosure was not related to the outcome variables.