This meta-analysis investigated the effects of learning video games on mathematics achievement of PreK-12th-grade students compared with traditional classroom instructional methods. Results from the 24 collected studies showed heterogeneity among effect sizes, both in magnitude and direction. Using a random effects model, a small but marginally significant overall effect ([d-bar][subscript RE]=0.13, p=0.02) suggested that mathematics video games contributed to higher learning gains as compared with traditional instructional methods. In addition, moderator analyses were mixed in terms of statistical significance and explored effect-size heterogeneity across effects using grade level, instrument type, length of game-based intervention, country, publication type, and study year characteristics. Overall findings indicate that video games are a slightly effective instructional strategy for teaching mathematics across PreK-12th-grade levels.