In this study, Michael Immendörfer examines the relationship between the New Testament letter to the Ephesians and the ancient city of Ephesus, which had the great Artemis as its goddess. He seeks to make a contribution to the discussion on the extent to which conclusions can be drawn concerning the local-historical explanation of New Testament epistles by viewing the latter through the lens of Greco-Roman cultic practices. Thus the contents of Ephesians are compared with the abundantly available archaeological and epigraphical sources of the Asia Minor metropolis. This endeavour reveals that the letter contains numerous unequivocal references to the cult of Artemis, a nexus suggesting that the author was very familiar with the historical background of ancient Ephesus and contextualised his letter accordingly for the intended readers who lived in this particular cultic environment. Drawing on the sources concerning ancient Ephesus, especially inscriptions, provides a plausible local-historical explanation of Ephesians, an epistle that has been an enigma to New Testament scholarship for decades in this regard.