Résumé : This paper analyses politicised Muslim identity among second-generation Turkish and Moroccan Muslims in five European cities. The research aims to investigate the joint impact of perceived discrimination and religious identification on politicisation processes. We distinguish support for political Islam from political action as distinct forms of politicised Muslim identity. The comparative findings reveal simultaneous processes of politicisation and de-politicisation of Muslim identity with reactive religious identification as a crucial mediator (Study 1) and with forms of politicisation as a critical moderator (Study 2). Using large-scale survey data, Study 1 estimates multi-group structural equation models of support for political Islam across nine intergroup contexts in Belgium, the Netherlands and Sweden: As expected, Muslims who experienced more discrimination identified (even) more strongly as Muslims; and high Muslim identifiers were most ready to support political Islam. At the same time, negative direct and total effects of perceived discrimination suggest the de-politicisation of a stigmatised Muslim identity. Using separate subsamples across four intergroup contexts in Belgium, Study 2 adds political action tendencies as a distinct form of politicisation. As expected, religious identification positively predicts both forms of politicisation, whereas perceived discrimination has differential effects: more experienced discrimination made Muslims weary of supporting political Islam, yet more ready to engage in political protest. To conclude, our research confirms the pivotal role of religious identification and distinguishes between political activism and other forms of politicisation.