The current study is concerned with the stability of and changes in vocational interest profiles and interest congruence in vocational education and training (VET). Specifically, we examined 1) the stability of vocational interest profiles, 2) the existence of occupational socialization effects that manifest themselves as increases in person-environment (P E) congruence, and 3) the question of whether or not changes in P-E congruence are psychologically relevant because they are related to trainees’ attitudes towards their VET course. We used data from a three-wave longitudinal sample comprising N = 2,611 trainees from five different VET courses in Germany. Through the use of meta-analytical aggregation techniques, we were able to analyze interindividual differences in intraindividual interest stability and P-E congruence and to relate these differences to trainees’ satisfaction with VET. On average, interest profiles turned out to be highly stable over the entire course of VET. However, we found substantial interindividual and intergroup differences in interest stability. Average P-E congruence increased slightly in two groups, providing only little evidence for the presumed socialization effects. Nevertheless, interindividual differences in P-E congruence and changes in P-E congruence were psychologically relevant because they were linked to trainees’ satisfaction with their VET course and changes therein.