Despite the growing body of studies on gamification, there is a paucity of research investigating the specific emotional outcomes of gamified experiences. Most gamification studies have focused primarily on positive emotions such as enjoyment. In addition, most gamification studies in educational contexts have been conducted with undergraduate students. To address the gaps in the literature, the present study examined the impact of gamification on doctoral students' perceptions of gamification and their learning in an online environment. Further, it explored what kinds of emotions they felt before, during, and after the gamified learning experience and what factors contributed to their positive and negative emotions. The study was conducted in an online, doctoral-level course, which was offered at a public university in the United States. The game elements used in the course included challenges, points and extra points, unannounced badges, choices, team collaboration and competition, and voting. The results of the study shed light on various emotions experienced by doctoral students in the gamified learning context, major factors contributing to both positive and negative emotions, as well as the impact of gamification on their attitudes and learning.