BACKGROUND In existing research on the importance of student breakfast, few studies have focused on the impact of breakfast on student cognitive development. Further, empirical research in this field is mostly based correlation analysis, in which it is difficult to control the influence of selection bias on the analysis results. MATERIAL AND METHODS Here, we used student academic performance, based on the academic quality monitoring data of Jiangsu basic education students, as a proxy variable for cognitive development, and used both ordinary least-squares regression and propensity score matching methods to analyze the impact of eating breakfast on the cognitive development of primary and middle school students. RESULTS We found that it is still common for students in primary and secondary schools to go without breakfast, and that this is even true in middle schools. Whether students eat breakfast is affected by many factors, and the frequency of eating breakfast has a significant positive impact on student achievement. CONCLUSIONS In primary school, students who eat breakfast every day in a week scored 31.322 points higher in academic performance than those who did not. In middle school, students who ate breakfast on time every day had significantly better academic performance (31.335 points higher) than those who did not eat breakfast every day. This indicates that eating breakfast every day has a significant effect on the cognitive development of students.