We predict real-time fluctuations in employees' positive and negative emotions from concurrent appraisals of the immediate task situation and individual differences in performance goal orientation. Task confidence, task importance, positive emotions, and negative emotions were assessed 5 times per day for 3 weeks in an experience sampling study of 135 managers. At the within-person level, appraisals of task confidence, task importance, and their interaction predicted momentary positive and negative emotions as hypothesized. Dispositional performance goal orientation was expected to moderate emotional reactivity to appraisals of task confidence and task importance. The hypothesized relationships were significant in the case of appraisals of task importance. Those high on performance goal orientation reacted to appraisals of task importance with stronger negative and weaker positive emotions than those low on performance goal orientation.