Although instructional leaders increasingly acknowledge the influence of emotion on student learning, the role of emotion in teachers' professional learning has received less attention. In this conceptual article, we draw on three psychological perspectives--cognitive, organizational, and developmental--to provide instructional leaders with an overview of the role of emotion in professional learning. Given the emotional complexities of teachers' work, we explain how the affective aspects of learning are particularly salient during teachers' professional learning opportunities. We provide instructional leaders with recommendations to optimize both the design and implementation of professional learning based on understandings of teachers' emotions.