This thesis comprises two articles based on qualitative empirical studies and a theoretical introduction. All three texts deal with the same problem area concerning musical meaning making and the concept development process in the course of composition learning. Each text could be read separately. The composition tasks in the empirical studies are both in electroacoustic music but the research problems and findings concern a broader sense of composition learning and even musical learning in general. The corpus of music education research on composition, rarely takes the body of artistic research and development literature into account, which means that contem- porary techniques and aesthetic discussions commonplace in composition education practice are not considered in music education research. This the- sis contributes to the research field of music education by acknowledging some of the fundamental research on composition, and discussing it from an education perspective. As a consequence, a contribution salient in the arti- cles is to begin to develop research methodology accordingly. The introduc- tion takes on a quest to map out the field in a new way by bringing together research in music education with artistic research on composition, writings on music philosophy, semiotics and cognitive psychology. The boundaries and interplay between semantic significance and syntactic meaning are ex- amined and discussed, as is the relation between aesthetic meaning making and learning. The articles deal with these issues in the context of composi- tion learning at a music program in upper secondary school. The one entitled Synthetic Activity is about fundamental aspects of soundgeneration and hence directed towards semiotics in the form of phonology and significance in connection to musical gesture and spectral content. The learning and meaning making processes of two composition students are studied as they engage in additive synthesis to build sounds, musical phrases and eventually a short musical composition. One of the most striking results is that the pro- ject came to be as much a listening experience as one of creative music mak- ing, and that the concept development process included rehearing and reas- sessing familiar sounds and music. The article Creative Structures or Struc- tured Creativity deals with form and syntactic structure, as the students learn to develop and apply composition algorithms to further their creative think- ing. The results show that there are several different layers to the concept development processes in this project. One layer concerns to be able to struc-7ture musical parameters on an aggregate level; to learn to plan musical de- velopments as space of possibility rather than as a determined linear se- quence of musical events. Another layer comprises problems of learning the programming environment and how to embody the musical algorithms in working computer-code. A third layer concerns letting the algorithmically generated materials influence your creative thinking. Tokens of the concept development process as described by Vygotskij (1987, 1999) in language- based learning were prominent also in the music composition learning of these studies. Implications for further research include formalizing criteria for the developmental phases of the concept development process in musical contexts.