Teacher effectiveness literature has supported the contention that a recurring theme in examining the qualities and attributes that constitute effective teachers is the use of humor in the classroom. However, most of the research did not appear to consider the potential differential effects on the students' perceptions of teachers' use of humor when taking into consideration the gender of the instructor. One study (Karle-Weiss, Newman, 1990) found that in a small sample of preservice teachers (N=70), there was a significant interaction in that female instructors who used humor were rated significantly higher on professionalism. This study, using a sample group of 255 preservice teachers, replicated the previous study, adding a control for appropriateness of humor. The survey instrument used was the teacher evaluation form in use at the University of Akron, Ohio, with four items added: instructor's sense of humor, amount of material used, appropriateness of humor, and professionalism of the instructor. While the overall general conception that humor is related to perceived instructor effectiveness was strongly supported, the expected interaction between instructor gender and humor in predicting perceived instructor effectiveness appeared to be somewhat questionable. Data resulting from the study are displayed in 17 tables. (JD)