We present the results of a meta-analytic synthesis of the literature on the association between the use of frequent low-stakes quizzes in real classes and students’ academic performance in those classes. Data from 52 independent samples from real classes (N = 7864) suggests a moderate association of d = .42 between the use of quizzes and academic performance. Effects are even stronger in psychology classes (d = .47) and when quiz performance contributed to class grades (d = .51). We also find that performance on quizzes is strongly correlated with academic performance (k = 19, N = 3814, r = .57) such that quiz performance is relatively strongly predictive of later exam performance. We also found that the use of quizzes is associated with a large increase in the odds of passing a class (k = 5, N = 1004, odds ratio = 2.566).