The current study examined undergraduate student understanding of, and interest in, course material as potential antecedents to student experiences of flow within a classroom setting. In addition, the social, informative, and contagious nature of flow were examined, as was the influence of being in flow during classroom coverage of material on subsequent quiz performance. Data from 14 students in an intensive course were collected over 15 days. All students provided ratings of their mood at the start of each class and ratings of their experienced flow, their interest in and understanding of material, and perceptions of their classmates' and the instructor's flow at the end of each class. In addition, the instructor provided ratings of her flow and perceptions of the class at the start and end of each class. Finally, students completed daily quizzes over the previous day's material. Results revealed that, controlling for prior mood, understanding of and interest in material were related to daily reports of flow experiences. In addition, evidence for the social validation and contagion effects of flow emerged. Contrary to expectations, flow during knowledge acquisition was not related to subsequent quiz performance over the material. Practical and theoretical implications are discussed.