This article reports part of the results of a larger study, where the goal was to explore music composer's representations of music composition. Previously published interviews of 57 established vanguard contemporary music composers (based across continents) were subject to a thematic analysis, validated by an independent analysis of a percentage of those interviews. The analysis revealed two overarching dimensions relating to learning. The first of those dimensions referred to the experience of developing the competency to compose and the second dimension referred to learning as changing through composing. First of those dimensions involves a diversity of aspects (i.e., learning context, learning process, learning product), for which a variety of notions emerged from the interview analysis. Second dimension also comprises a variety of aspects (i.e., insights on other realities, insights on sounds, increased self-awareness). Implications for the teaching and learning of musical composition are drawn.