The aim of this meta-analysis was to investigate effects of family literacy programs on the emergent literacy skills of children from low socioeconomic status families (0–6) and to establish which program, sample, study, and measurement characteristics moderate program effects. Outcomes of 48 (quasi-)experimental studies covering 42 different programs revealed a medium average effect of Cohen’s d = 0.50 on immediate posttests and a marginal average effect of Cohen’s d = 0.16 on follow-up measures. Together, effects of different moderator variables indicate that children benefit from targeted programs that focus on a limited set of activities and skills and that are restricted to one (training) context. Additionally, we found larger effects in experimental studies and when researcher-developed tests were used. Our outcomes not only provide guidelines for program developers but also call for more longitudinal research that examines how positive short-term changes as a consequence of program participation can be sustained over time.