Marriage and relationship education (MRE) recently has become a tool of public policy to help couples form and sustain healthy marriages. With increased public funds comes increased public scrutiny. In this meta-analytic study, we examined the effects of MRE on two common outcomes: relationship satisfaction/quality and relationship communication. A thorough search produced 133 codable reports that yielded 197 studies and nearly 600 effect sizes. We report effect sizes separately by study design groups. The effect sizes for relationship satisfaction/ quality were generally in the d = .30-.40 range, while the communication effect sizes were somewhat larger, generally in the d = .40-.70 range. We also employed a large number of methodological, sample, and intervention moderators to examine the substantial heterogeneity of these effect size distributions. Moderator analyses yielded some interesting findings relevant to the work of MRE practitioners. While MRE evaluation studies now provide ample evidence of their effectiveness, there are important deficits in this work especially for guiding public policy. We discuss several important deficits and make suggestions for further research. (Author abstract)