Accumulating research points to the importance of incremental theories of emotion. Yet, little is known about whether these beliefs change in adulthood across long time spans, and if so, whether such changes are prospectively linked to emotion regulation outcomes. In the present investigation, we tested how incremental theories of emotion change during college, and whether such changes are linked to emotion regulation practices. We followed 394 undergraduates as they entered and ultimately graduated from college. Focusing on the temporal dynamics of incremental theories of emotion, we found that they were somewhat stable, and their mean-level increased over time. Focusing on the correlates of such changes, we found that students who during college came to believe that emotions (but not intelligence) are more controllable, ended up using more cognitive reappraisal (but not expressive suppression) at the end of college. Similarly, students who during college came to use cognitive reappraisal (but not expressive suppression) more frequently, ended up believing that emotion (but not intelligence) is more controllable at the end of college. This pattern could not be explained by differences in initial levels or by differences in underlying affective experiences. We discuss potential implications of these findings for understanding the interplay between beliefs and emotion regulation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).