In this article, we present the results of a study about the perceptions of students studying for a degree in primary education about their music-teaching knowledge and their training needs in that area. The study was carried out in three public universities in Galicia (Spain). Using a quantitative methodological approach, a questionnaire was used to collect data from 302 participants. The results indicate some gaps in their practical, theoretical, and teaching knowledge related to musical expression which would have to be addressed through continued training during their professional practice. These gaps could also be considered in the design of teaching plans for teachers' initial training. Considering that music is part of the primary education curriculum, and most people's daily lives, careful thought is needed about the elements making up future teachers' training. The measures which are adopted as a result will determine the use that will be made of music, both academically and as an interdisciplinary teaching resource.