Globally, students demonstrate considerable heterogeneity in academic performance even under similar conditions. While previous systematic reviews have provided a more comprehensive picture of the relationship between different factors and academic performance, none have investigated its relationship with brain activity. Previous evidence supports that the P3, a positive deflection in the electroencephalogram reflecting higher order cognitive processes, may serve as a neuromarker for academic performance. The primary objective of this systematic review was to synthesize existing research on the P3 and academic performance in healthy adults. Searches were conducted using Web of Science, ProQuest, and Scopus databases. In total, four studies met the eligibility criteria for inclusion in the present review. Results suggest that P3 latency can serve as a reliable neuromarker for academic performance in healthy adults. However, limited previous studies and methodological differences prevent strong conclusions from being drawn. Further research is needed to establish the predictive capability of the P3 on academic performance. This paper represents the first systematic review on this topic, illuminating our understanding of the relationship between brain activity and academic performance.