According to the Entertainment Software Association (2020), 70% (51.1 million) of children under the age of 18 are gamers in the United States and consume an average of two and a half hours per day playing digital-based games, making these games one of the most widely known leisure activities worldwide. Today's Net Generation (Kindergarten through graduate students) has never known a world without the Internet, with 20% of them first using computers between the ages of five and eight (Dede, 2005; Oblinger & Oblinger, 2005). The Net Generation had been exposed to subject materials in schools used for many years but not to the digital media they had played while growing up. Combining digital gaming with educational content could help students in the understanding of academic content. Stealth assessment games were shown to be effective learning tools in which learning tasks were unobtrusively embedded for specific knowledge and skill-based outcomes to be measured without the students being aware that they are being evaluated. This qualitative multiple case study explored teacher perceptions of how stealth assessment games influenced teaching and learning in the middle school mathematics classroom. This research study revealed several patterns of how and why stealth assessment games could be effective tools to guide instruction and help support increasing mathematical knowledge for middle school students. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]