Research question: The present study examined the extent to which emotional experience and emotional competence (EC) change in people with chronic pain during interdisciplinary multimodal pain treatment (IMPT). Methods: The study included N = 184 adult German-speaking individuals with non-cancer-related chronic pain. They completed a day clinic IMPT. The frequency of specific emotions (anger, etc.) and EC was assessed at three measurement time points using the Questionnaire for Emotion-Specific Self-Assessment of Emotional Competencies (ERSQ-ES) and the Emotional Competency Questionnaire (ECQ). The course results were analyzed descriptively, inferentially, and using linear regression. Results: Positive emotions were experienced more frequently (effect size r = 0.40; p < 0.001) and negative emotions less frequently (r = 0.39, p < 0.001) at end of therapy. The experience of anger decreased particularly strongly (r = 0.52; p < 0.001). Self-assessed EC did not change during the IMPT (χ ²_{ECQ_total} (2) = 0.09; p = 0.956). EC largely explained the variance in the frequency experience of positive (R ² = 0.468) and negative emotions (R ² = 0.390). Discussion: Improvements in patient-reported frequencies of positive and negative emotions during IMPT were demonstrated. Further research should validate these results using a control group. Even though no explicit increase in competence was perceivable for the studied subjects, EC had a high predictive value for emotion frequency. Future therapy designs and evaluations should focus more on changes of emotional experience.