The aim of this study is to introduce an educational game called The Star Game, and to examine its effects on prospective science teachers' conceptual understanding of stars. In addition, their opinions of The Star Game were examined. The study was conducted with a total of 54 prospective teachers in three groups. The Star Game was played in all three groups and data was collected using the Star Properties Concept Inventory and the Star Game Opinion Questionnaire. The conceptual understanding on the stars increased significantly in all three groups after the application. The Star Game was described as enjoyable, interesting, instructive, and promoting a positive classroom environment, and a valuable educational activity for the profession. Criticisms included the length of answers, the noise caused in the classroom, and the time required.