Educational games have to be well designed to incorporate learner engagement, an integral component of educational effectiveness. One foundation of designing educational engagement is flow theory. This article presents a flow framework that describes the building blocks of flow experience that can be used to design appealing and effective educational games for formal and informal learning contexts. The framework provides the principles for good educational game design, based upon associative, cognitive and situative learning theories, including engagement and pedagogic elements with a focus upon feedback and flow principles. Furthermore, the paper clarifies the relation between the flow experience and immersion. We tested the flow framework in the RealGame case study, which revealed that the RealGame business simulation game was well designed and effective at engaging students. We found that the university students’ flow experience in the game was high and the findings indicated that sense of control, clear goals and challenge-skill dimensions of flow scored the highest, but a rewarding experience and feedback dimensions also scored highly by the students. Overall, the results indicate that flow framework is a useful tool in studying game-based learning experiences