This study uses meta-analytic methods to explore programmatic moderators or common factors of the effectiveness of marriage and relationship education (MRE) programs. We coded 148 evaluation reports for potential programmatic factors that were associated with stronger intervention effects, although the range of factors we could code was limited by the lack of details in the reports. Overall, we found a positive effect for program dosage: moderate-dosage programs (9-20 contact hours) were associated with stronger effects compared to low-dosage programs (1-8 contact hours). A programmatic emphasis on communication skills was associated with stronger effects on couple communication outcomes, but this difference did not reach statistical significance for the relationship quality/satisfaction outcome. There was no evidence that institutionalized MRE programs (formal manuals, ongoing presence, formal instructor training, multiple evaluations) were associated with stronger effects. Similarly, there was little evidence of differences in program setting (university/laboratory vs. religious). We discuss possible explanations for these findings and implications for program design and evaluation. (Contains 1 table.)