This article explores how Muslim identity is constructed in different ways by two groups of political activists in Britain. At the heart of our investigation is an interest in how these different definitions of Muslim identity are organized to promote different forms of political action. We pay particular attention to how these groups employ the same Islamic concept, da'wah (the injunction to invite people to Islam), and show that it only gains meaning when invoked and deployed in the context of practical argumentation. That is, the meaning of such concepts is not a fixed given but highly contingent upon the contrasting strategic concerns of those claiming to represent the community. While these points have a general applicability, they are particularly important in the analysis of Muslim political activity. For too long, the ahistorical essentialist assumptions of 'Orientalism' have obscured the fundamentally contested and strategically constructed nature of Muslim identity.