International literature has reported that teachers present deficiencies and insecurities in teaching music; consequently, music is not taught competently and appropriately. Self-efficacy is the belief in one's ability to cope with different situations and tasks to produce achievements according to the individual's conviction. This systematic literature review aims to examine the self-efficacy of teachers who teach music within classrooms in studies conducted between the years 2011 and 2021. Articles were reviewed from the Web of Science, Scopus, and EBSCO databases, using the thematic analysis methodology and inclusion criteria, and fifteen articles were finally selected. The results indicate a clear difference in self-efficacy between specialist and non-specialist (generalist) teachers. In both cases, teachers look for different ways to teach music despite the adversities they face in their educational institutions, the low priority of the discipline within the school curriculum, and the scarce musical education they had in their teacher training. As a consequence, their level of self-efficacy is affected according to their professional and life experiences.