Research on the quality of second language teaching has recently highlighted the need to consider not only cross-curricular but also domain-specific dimensions of instructional quality. In this study, theoretical assumptions about domain-specific determinants of interest and performances in second language acquisition are tested, using data from a sample of 1 655 eighth graders in three Swiss cantons: Fribourg, Lucerne, and Valais. Factor analysis yielded five factors related to teaching dimensions of French as an additional language: use of French in lessons, intensity of language use and practice, use of authentic material, vocabulary learning, and communication with native speakers. Subsequent multilevel analyses showed that using French in lessons, as well as intensive language use and practice are significantly associated with the students performances and the interest the develop over a 1-year period. Vocabulary learning has no effect. Contrary to expectations, there is a negative relationship between communicating with French native speakers and the development of interest for learning French as a second language.