The title of this essay assumes that “church” was an operative category for those second-century Christian authors whose writings are included in the collection called “the Apostolic Fathers.” Such an assumption is valid, provided that it is accompanied with the caveat that the Greek noun ekklēsia, which is typically rendered with the English word “church,” is but one image among many used to describe communities of Christ-followers in these writings, even as ekklēsia is of particular importance because it is found as a designation for these groups in each of the documents under consideration in this essay. Another necessary qualification is that statements about and reflections on Christ-following ekklēsiai (“churches, assemblies”) in the writings of the Apostolic Fathers are contingent and not systematic. The modern theological discipline of “ecclesiology” tends to frame its considerations of the identity and mission of the church in conversation with Scripture (especially the New Testament) and tradition. Yet the second-century writings known as the Apostolic Fathers were penned before there was a New Testament as such and at a time when Christian tradition was yet in its infancy. Thus, we find in these important nascent witnesses snapshots of early Christ-followers debating and defining the identity, mission, and organization of their groups. In order to manage the disparate available evidence from 1 Clement, 2 Clement, the Letters of Ignatius, the Letter of Polycarp to the Philippians, the Martyrdom of Polycarp, the Didache, the Epistle of Barnabas, the Shepherd of Hermas, and the Epistle to Diognetus, this essay concentrates on three separate but related questions: (1) How is the identity of the church presented? (2) What is the work of the church? (3) What, if anything, is said about the ordering and structures of the church?