There are different churches and church-related actors who are engaged in diaconal action. Diaconal collaboration among these actors is important for mutual learning and to achieve greater impact. In the Lutheran communion, the LWF member churches are implementing diaconal programs in their contexts. At the same time, the churches have mandated World Service as their global instrument for international diakonia. The Guidance Note ‘Joint Engagement of Worlds Service Programs and Member Churches’ aims to provide inspiration and practical recommendations for meaningful joint engagement of LWF’s member churches and the World Service country and emergency programs. It is offered as a resource to affirm and deepen mutual understanding of the joint calling and distinct mandates of LWF’s humanitarian and development arm and the churches’ witness. The four case studies featured in the publication illustrate good practices of existing collaboration. In a wider sense, this document may also provide some orientation for LWF’s programs that work in collaboration with other faith-based communities.