This study was designed to examine the effects of disposition, sex, and a positive mood induction on student evaluations of teachers. In 33 laboratory classes, 339 students filled out measures of negative affectivity (NA) and positive affectivity (PA). Several weeks later, participants filled out a research-based teacher evaluation form. Students in half of the classes received a positive mood induction prior to filling out the evaluation form, whereas participants in the other classes received the positive mood induction after filling out the evaluation form. Results indicated that PA and the positive mood induction both related positively with evaluation measures. Moreover, NA and PA moderated the relationship between the positive mood induction and teacher evaluations for males, but not for females. Implications for organizations and suggestions for future research are discussed.