► We examine the relationship between religiosity and civic engagement using Portraits of American Life Study national survey data. ► Religiosity positively related to multiple civic outcomes. ► Relationship between religiosity and civic engagement is often explained by religious social networks, not beliefs or affiliation. ► Religious networks have stronger impact on civic engagement than general social networks. ► Having social networks from a religious congregation is associated with increased civic participation, though the specific mechanism at work is unknown. A substantial literature has found that religiosity is positively related to individuals’ civic engagement and informal helping behavior. Concurrently, social networks as sources of information and encouragement have been suggested as the mechanism underlying phenomena including successful job searches, improved health and greater subjective well-being. In this paper we use data from the Portraits of American Life Study (PALS) to examine whether religiously based social networks explain the well-established relationship between religion and civic engagement. We test potential mechanisms including beliefs, affiliation, and social networks, and we find that having a strong network of religious friends explains the effect of church attendance for several civic and neighborly outcomes. We suggest this phenomenon may exist in other, non-religious, spheres that also produce strong friendship networks.