Teaching for the first time can be a challenging but rewarding experience. For first-time graduate student instructors, however, it also officially marks the transition from student to teacher--a process that can be both transformational and emotion-laden. In this article, we use content analysis of 86 first-time sociology graduate student instructors' reflections on their first semester teaching to explore the emotional aspects of first-time college teaching, an aspect that has received little attention in the existing literature. We describe the range of emotions--both positive and negative--first-time instructors highlighted in these written reflections, as well as their discussions of emotional highs and lows, emotional surprises, connections to pedagogical strategies, and the role of formal and informal departmental support in dealing with the emotional aspects of teaching. We conclude with the implications of these findings for graduate student teacher training and preparation programs and directions for future research.