Insofar as the twentieth century has often been referred to as 'the ecumenical century', the twenty-first seems poised to be known as 'the century of World Christianity'. Into this situation, the study seeks to show the ongoing relevance of Wolfhart Pannenberg's ecclesiological and ecumenical proposals and, in doing so, finds that his eschatologically-oriented and historically-rooted emphasis upon an 'open-ended distinctiveness' is exactly the corrective World Christianity needs if it wants not only to stay contextually 'open-ended', but remain 'distinctively' Christian as well. The first study to place Pannenberg's ecclesiology in direct conversation with World Christianity.