In recent years, grit has drawn increasing attention from both researchers and practitioners. As an important noncognitive indicator, grit has been used to understand individual success and performance in various fields. However, past empirical research has shown inconsistent findings on the relationship between grit and academic achievement. This study aims to review and synthesize past empirical findings on the relationship between grit and academic achievement. Forty-four relevant articles involving a total of 60,133 participants met the inclusion criteria and were synthesized in this meta-analysis. Our findings suggest that (a) overall grit level and its two facets (consistency of interest and perseverance of effort) are positively associated with academic achievement; (b) the association between grit and academic achievement is moderated by grade level; and (c) perseverance of effort shows the largest effect size on students’ academic achievement when compared with overall grit level and consistency of interest.