Most studies evaluating the effectiveness of school internships have relied on self-assessments that are prone to self-presentational distortions. Therefore, the present study analyzed the improvement in the instructional quality of 102 student teachers (46 women) from a German university during a 15-week internship at a local secondary school across three rating sources: the student teachers themselves, their students, and their mentors (experienced teachers). A latent multimethod change analysis identified a significant increase in instructional quality during the practice semester. However, ratings from the three informant groups only marginally converged.