Autism spectrum disorder is a complex neurological disorder characterized by impairments in communication and social interaction, limited patterns of behavior, interests and activities. Given the different forms of autism spectrum disorder and the fact that no two people are the same, an individual approach to each individual is required. Musical ability is one of the special talents that a child with an autism spectrum disorder can have. Such a child should be allowed to practice music. As a therapy, music therapy has proven to be effective in working with children with autism spectrum disorder, i.e. it has a positive effect on communication, vocalization, joint attention, eye contact, concentration, cooperation, cognitive functions, social skills, etc. This paper presents the observations obtained through the study case. The aim of the research was to show the behavior of students with autism spectrum disorder in the Music culture class and the impact of music therapy on their behavior. For the purposes of the research, two interviews were conducted, i.e. with a teaching assistant who worked with a student with an autism spectrum disorder and with the student's parents. The case study showed that the student has a developed musical ability, that he participates actively, with reserved attention, only in the Music culture classes, and that music therapy helped him in his expression and speech. It is essential to give these kids the tools they need to further develop their musical abilities. It will contribute to children with autism spectrum disorder feeling safe, happy, and accepted in their environment.