Struggling math students often have difficulty developing a sense of self-efficacy and intrinsic motivation to learn math, which has been found to predict future math achievement (Pitsia et al., 2017). Conventional methods of math instruction and assessment may provoke elevated levels of math anxiety for many students, which has been found to negatively impact math achievement (Wu et al., 2012). Numerous studies have examined the applications of using digital-game based learning or instruction with educational video games to foster improved learning outcomes, a strategy which has been shown by metanalytic research to significantly improve K-12 students' motivation in mathematics (Fadda et al., 2022). Minecraft Education, released in 2016 by Microsoft, is a serious educational game, or a virtual immersive three-dimensional environment used for directed educational purposes. This educational software is a modification of the globally popular multiplatform video game Minecraft, the third-best-selling video game in history (Thompson, 2016). While Minecraft Education could be an invaluable tool for enhancing intrinsic motivation to learn and to address many students' unique learning needs, there is limited quantitative research demonstrating the program's effectiveness for addressing specific skill deficits in academic domains. The present study sought to address several of the current limitations in empirical research by utilizing a quantitative quasi-experimental group design methodology to assess the effectiveness of Minecraft-based instruction for improving student achievement in math, specifically geometric measurement of volume of rectangular prisms (Common Core Math Standards, 5.MD.C.3, 5.MD.C.4, and 5.MD.C.5). This research also explored the use of Minecraft as an academic assessment tool. In addition to analyzing the convergent validity of Minecraft math assessments and pen-and-paper quizzes addressing the same common core math standards, the researchers administered questionnaires to investigate whether game-based assessment would be found to reduce students' testing anxiety compared to conventional pen-and-paper assessments. The study was conducted in the afterschool setting during the LearningWorks AfterSchool Program (LWAS), which offers free STEM programming instruction to students performing below grade level. Instructional and problem-solving strategies utilized in the intervention were aligned with the Universal Design for Learning Framework to maximize student engagement and accessibility of learning activities. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]