School-based financial literacy programs have diffused broadly, but their effectiveness in reality is surprisingly complex. This systematic review aggregates empirical evidence from experimental and quasi-experimental studies to clarify whether these educational interventions are effective in implementing their intended impacts. The findings reveal a chronic paradox: programs consistently improve financial understanding and attitudes among students, but it is much more challenging to translate this knowledge into actual financial habits. Meta-analytic evidence shows large gains in knowledge (+0.33 standard deviations) but not in behavioral change (+0.07 standard deviations). Follow-up studies over longer periods of time show that early financial education can lay the basis for later decision making, yet immediate behavioral change remains evasive. Demographic factors have a heavy impact on program success, with lower socioeconomic students, foreign-born households, and low-track schooling history showing inconsistent response patterns. Quality of implementation varies wildly by site with results being significantly influenced. The review mentions promising approaches like experiential learning experiences, differential interventions for specific groups, and integration within existing curricula rather than as distinct courses. Unrealistic expectations for short-term behavior change can complicate program planning. Future research should prioritize long-term follow-up studies, implementation factors should be examined more critically, and better behavioral measures of outcome should be constructed to assist evidence-based program planning.