Most higher education institutions offering programmes in music performance organise master classes for their students. It is commonly agreed that master classes offer valuable learning opportunities for the students performing, but what do they offer for students in the audience? In this article, theories of learning by observation as well as research on peer learning and assessment are used to discuss the learning potential of master classes for students who are not performing themselves. It is concluded that students can definitely benefit in many ways from attending master classes as an audience, and suggestions are given on how to enhance the learning outcome.