Although there is an extensive body of literature that investigates the process and outcomes of children’s collaboration on scientific reasoning tasks, very little work has focussed on the nature and quality of children’s collaboration on creative tasks. One study reported here used a questionnaire to music teachers to ask about their typical design of musical tasks in the classroom and the factors that influenced these decisions. A further study reported here investigated the effects of friendship, gender and previous musical experience upon the interactional processes and musical outcome of children’s collaborative compositions. The design included comparison between friendship pairs and non-friendship pairs and also between males and females, with 11–12 year old children at an English middle school. All pairs consisted of one child with previous musical experience and one child without. All compositional sessions were video taped and the musical and verbal elements were coded with reference to the proportion of transactive and non-transactive elements present. Results demonstrated that the communication (both verbal and musical) between the friendship pairs was qualitatively different from the communication in the non-friendship pairs. Specifically, the friendship pairs showed more transactive communication and, when a teacher rated the final compositions, the friendship pairs scored significantly higher. Multiple regression analysis highlighted that the amount of transactive communication was a significant predicator of the quality of the children’s composition. The results are discussed with reference to the nature of communication, the impact of friendship and the assessment of creative work.