Music has an important place in theatre productions and in instructional audiovisual material. Why is this, what functions has the music and what are its effects? Literature on music in audio‐visual material and on its design is very scarce. The concept of music and its characteristics are described in some detail, indicating that music per se has no referential meaning. The theory is presented that music has an emotional effect that can be manipulated by the developer of audio‐visual material. On the other hand, music offers resources for commenting and structuring audio‐visual material.