In recent decades, the teaching and learning of composition has become an important topic for research in music education. Composition is established as one of the three main areas in the Norwegian curriculum "Laereplanverket for Kunnskapsløftet" (LK06, 2006), and the importance of creative competencies is being increasingly recognized worldwide, inside and outside formal music education institutions. A central research topic within the field of music education addresses the issue of how to facilitate and lead creative musicking projects. This article examines a composition workshop in which pupils from several Norwegian municipal schools of music and performing arts participate. The aim of the workshop was to create a new piece of music that would be performed at the end of the project period. An experienced composition workshop leader led the project, and four professional musicians took part. The empirical data for this study consisted of interviews, participant observation and video-recordings. Analyzed from a sociocultural perspective, the findings led to a deeper understanding of the facilitation role, revealing that it consists of multiple modes, such as scaffolding, co-participation and collaboration, as well as management and distribution of cultural tools. These findings are discussed in terms of understanding the complex knowledge and skills needed to facilitate creative musicking practices.