Instructor credibility, or the degree to which an instructor is perceived by his or her students to be competent, to have character, and to be caring, is one of the most important variables affecting teacher-student interaction. However, gender role stereotypes may place female instructors at a disadvantage when it comes to perceptions of their credibility, as students may have difficulty seeing women in positions of authority as both competent and feminine. The purpose of this study was to examine the relationships between students' perceptions of instructors' credibility, gender role, and communication style; to analyze ways students describe their instructors; and to assess how well male and female instructors meet the expectations for a good instructor. This study found that good male instructors were more often considered credible and assertive, while good female instructors were more often considered caring and responsive. These findings are significant because they suggest students have different expectations for what constitutes good for a male instructor and what constitutes good for a female instructor. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]