The present study looks at pre-service teachers' beliefs about multilingualism in school and to what extent these can be influenced. It is based on the pre- and post-test evaluation of a seminar concept promoting linguistically responsive teaching, which was tested with N = 27 pre-­service teachers in Germany during the course of one semester. The evaluation was conducted using the DaZKom-beliefs survey, which measures pre-service teachers' beliefs about (1) Linguistic Responsiveness, (2) Responsibility for Language Facilitation, and (3) Valuing Multilingualism in a linguistically heterogeneous classroom. The study concentrates on the following questions: Does the course on linguistically responsive teaching have an effect on pre-service teachers' beliefs towards multilingualism in school? Do the scales reflect the course structure and its contents? The results suggest that the course had a positive impact on pre-service teachers' beliefs particularly with respect to the two scales (2) Responsibility for Language Facilitation and (3) Valuing Multilingualism that correspond closely with the course contents. The overall effect including all scales was highly significant. These findings provide further insight for teacher training programs as to if and how far it is possible to influence beliefs by means of targeted learning opportunities.