The transition to higher education is a topic of concern for educators around the world. In fact, the shift to a more competitive educational environment can negatively impact students' academic self-concept, which, in turn, might lead to lower persistence and less adaptive educational decisions. To examine how psychology students adapt to the transition to such an environment, the present article examines changes in psychology entrants' academic self-concepts. A four-wave longitudinal study covering students' first three semesters was conducted. Since the transition to higher education implies that students compare themselves to a stronger reference group, we expected academic self-concept to decrease over time (i.e. a big fish little pond effect). Moreover, we expected secondary school grades, study grades and gender to moderate self-concept development. While we found no evidence for a big fish little pond effect, we found that study grades and gender indeed moderate self-concept development: while self-concept scores of students with better grades increased with time, the contrary occurred for students with lower grades. Moreover, females' self-concepts remained largely constant whereas those of men increased considerably over time. We conclude that, in terms of self-concept changes, psychology undergraduates seem to adapt rather well to the transition to higher education. Future research should investigate whether or not these findings are generalisable to other academic fields, especially to disciplines that attract students with a broader range of achievements.