In this paper, we examine how social identity, moral obligation and the relationship between the two shaped support for the 2016 Academics for Peace petition in Turkey. We examine the pre‐trial statements of nine defendants charged for signing the petition and appearing in court on the same day in December 2018. We first conduct an inductive thematic analysis on one statement, and then, using the themes from this analysis, we conducted a deductive thematic analysis on the remaining eight statements. In line with the existing studies, we find considerable evidence that social identity and moral obligation are invoked as key reasons for signing in this highly repressive context. However, rather than these being separate factors, the two are reciprocally constitutive. That is, social identities define moral obligations and, at the same time, enacting moral obligations defines identity (both the position of the individual in the group and the nature of the group in the world). In discussion, we consider the broader implications of a moralized view of social identities for our understanding of both collective action and social identity processes more generally.