BACKGROUND On the one hand, achievement indicators like grades or standardized test results are strongly associated with students' domain-specific self-concepts. On the other hand, self-evaluation processes seem to be triggered by a self-enhancing means of information processing. As a consequence, above average students have more positive self-concepts than average students whereas below average students have lower self-concepts than average students. OBJECTIVE Imagine that two students, one above average, the other below average, have identical achievement differences to an average student. Will their self-concepts also share identical differences with the average students' self-concept? Our hypothesis is that students who achieve above average develop self-concepts that are more distinct from average achieving students' self-concepts than are below average achieving students' self-concepts. METHODS In Study 1, N=382 7th-10th graders (62.2% female) from several academic track (Gymnasium) schools in Germany served as participants. Students' ages ranged between 12 and 16 years (M=14.76, SD=6.24). In Study 2, the sample comprised N=1,349 students (49% girls) with a mean age of M=10.87 (SD=0.56) from 60 primary schools that were drawn representatively from a federal German state. In an experimental Study 3, N=81 German teacher education students (76.5% female) aged between 18 and 40 years (M=22.38, SD=3.80) served as participants. METHODS Two field studies and one experimental study were conducted. RESULTS In all three studies, achievement differences between above average and average students were identical to those between average and below average students. However, self-concept differences between above average and average achieving students were greater than those identified between average and below average students. CONCLUSIONS As our studies show, self-enhancement and self-protection processes lead above average students to develop self-concepts that are more distinct from average students' self-concepts than those of below average students' self-concepts.