This experimental study was intended to examine whether the integration of game characteristics in the OpenSimulator-supported virtual reality (VR) learning environment can improve mathematical achievement for elementary school students. In this pre- and posttest experimental comparison study, data were collected from 132 fourth graders through an achievement test. The same math problem-solving tasks were provided to the experimental and control groups in the VR learning setting. Tasks for the experimental group involved the game characteristics of challenges, a storyline, immediate rewards, and the integration of game-play in the learning content. Analysis of covariance with the achievement test results indicated a significant effect of game-based learning (GBL) in the VR environment, in comparison with non-GBL in the VR environment, in promoting math knowledge test performance.