This article explores the religious lives of migrants in the African diaspora by focusing on the case of the Missão Evangélica Lusófona (MEL), a congregation settled on the outskirts of Lisbon and formed by migrants from Guinea-Bissau and other Portuguese-speaking countries. MEL is portrayed as an example of how Christian faith enables African believers to cross transnational spaces and to create new spiritual placements in the local environment they inhabit. Against the background of postcolonial Portugal, MEL's mission discourses are analysed as narratives of moral empowerment that invert the stigmatizing representations of African migrants expressed by their Portuguese-born neighbours. Through these narratives, it is suggested, Evangelical Guinean migrants are able to face their historical and social condition of marginality, by developing a spiritual citizenship grounded in the idea of a Lusophone space of mission.