Emotions play a central role in educational settings, influencing both students' engagement and teachers' instructional practices. Despite growing recognition of the importance of emotion in education, little is known so far about how preservice teachers conceptualize emotions in students and how this may shape their pedagogical choices. This mixed-method study explored the beliefs of 292 Belgian and Swiss teachers in training about students' emotions, knowing that these emotional beliefs are crucial in influencing teaching practices, interactions and students' outcomes. Results showed that teachers attributed positive emotions such as interest and pride more to their own influence, whereas emotions such as joy and shame as externally driven. They saw emotions as variably useful depending on context: interest, pride, and joy being particularly useful for learning. Finally, beliefs in emotion malleability were linked to perceived utility only when aiming at enhancing relationships with the teachers. Findings emphasize the need to integrate emotional education in teacher training to provide scientific knowledge of the role of emotions in learning and teaching. Such integration could foster emotionally responsive teaching practices and enhance both teacher well-being and student success.