The evaluation of student work is a central aspect of the teaching profession that can affect students in significant ways. Although teachers use multiple criteria for assessing student work, it is not yet known if emotions are a factor in their grading decisions as has been found in other instances of professional evaluations. Reason to believe that this might be the case not only comes from emotion-congruent judgment research, but also from the emerging field of teacher emotion research which is beginning to reveal that emotion may be an important element in various teacher cognitions and practices. The present study provides initial evidence that emotions may bias the grades teachers assign to their students, such that positive and negative emotions influence grade assignment in emotion-congruent ways. This research offers empirical contributions to research on emotion and cognition as well as on teacher emotion.