Online learning has been gaining widespread adoption due to its success in enhancing student-learning outcomes and improving student academic performance. This paper describes an online tutorial to teach resource-event-agent (REA) data modeling in an undergraduate accounting information systems course. The REA online tutorial reflects a self-study application designed to help students improve their understanding of the REA data model. As such, the tutorial acts as a supplement to lectures by reinforcing the concepts and incorporating practices to assess student understanding. Instructors can access the REA online tutorial at http://smu.sg/rea. An independent survey by the University's Centre for Teaching Excellence found a significant increase in students' perceived knowledge of REA data modeling after using the REA online tutorial compared to their knowledge prior to using the tutorial. Students also rated their overall satisfaction with and the effectiveness of the REA online tutorial as high.