This study analyses the self-assessment behaviour and efficiency of 163 undergraduate business students from Hungary. Using various statistical methods, the results support the hypothesis that high-achieving students are more accurate in their pre- and post-examination self-assessments, and also less likely to overestimate their performance, and, if they do so, the mean overestimation is lower than in the case of lower achieving students. The study did not find a strong difference in the tendency to self-overestimation between sexes, but in their pre-examination prediction, women seem to overestimate significantly more than men. An overall tendency among the students to overrate their own examination performance is also detected, as is a tendency to increase the accuracy of self-assessment after sitting the examination.