Stereotypes are constantly utilized to draw inferences and evaluate information, regardless of whether or not individuals employing them are cognizant of this fact. However, when jurors who are responsible for evaluating the truthfulness and credibility of witness testimony rely on stereotypes regarding the emotional responses of men and women to judge witness testimony, the conclusions they draw may be tainted. In this study, six experimental conditions were constructed to ascertain whether witness testimony would produce different effects if male and female witnesses delivered testimony while showing emotions stereotypical of their genders or emotions unexpected of their genders. While testifying that they were the victims of an armed robbery, male and female witnesses showed fear, anger, or no emotion. It was found that when male witnesses displayed the stereotypical emotion for their gender, anger, the participants rated the guilt of the defendants significantly higher than when female witnesses displayed the same emotion. Conversely, when female witnesses displayed the emotion stereotypical for their gender, fear, the participants rated the guilt of defendants significantly higher than when men displayed fear. It was also found that female displays of anger and fear produced a much greater difference in guilt rating for defendants than male changes in emotion. Additionally, over all experimental conditions, witnesses were believed to be telling the truth most when they showed fear and least when they showed anger.