Research on generational differences in immigrant youths' academic achievement has yielded conflicting findings. This meta-analysis reconciles discrepant findings by testing meta-analytic moderators. Fifty-three studies provided 74 comparisons on academic outcomes. First- and second-generation youths did not significantly differ on academic achievement (Hedges's g = 0.01), and second-generation students performed slightly better than third-or-later-generation peers (g = 0.12). Moderation tests indicated that second-generation immigrants outperformed first-generation students on standardized tests (g = 0.20) and earned better grades than third-or-later-generation peers (g = 0.20). Immigrant advantage was stronger for Asian, low-socioeconomic, and community samples. Immigrant advantage may be overestimated in studies that use self-reported rather than school-reported achievement. Together, our results suggest a small, heterogeneous second-generation immigrant advantage that varies by immigrant population and study characteristics.