This chapter beings with a vignette of participation in a performance action by the environmental choir Shell Out Sounds, which sings songs against Shell and their sponsorship of cultural institutions. This story acts as a way of introducing one of the main case studies of the book, and sets out the main issues explored in the chapter: how collective identity is built in art activist groups and to what extent theories of collective identity are useful for the study of groups whose form of action is rooted in creative practice. The chapter looks at a number of actions by Shell Out Sounds and presents extracts from interviews and talks, in which members share their views on their own practice. Taking these stories and interviews as a basis, the chapter looks at how the aesthetic and political aspects of this group’s practice are negotiated in the construction of a shared identity, and how this process is informed by participants’ understanding of their actions, their different ideological positions on the potential of art as a political tool, and the frictions between different forms of identification with the collective, as a political group and/or as a choir. This chapter borrows from new social movement theories of collective identity and suggests how these theories can be expanded in order to understand the construction of identities for art activist groups specifically.