The Assembly Planning Committee for the Twelfth Assembly was constituted by the LWF Council in 2013 and met once in 2014 in Geneva and once in 2015 in Windhoek. The committee developed the broad guidelines for the concept, content and methodology of the Assembly. At the end of its work in June 2015, the APC handed over to the LWF Council the continuing task of overseeing the planning and preparations being undertaken by Communion Office staff as well as taking decisions on Assembly matters.
At its meeting in 2014, the LWF Council appointed members to the International Worship Planning Committee. The committee met in Geneva in March 2015, Windhoek in October 2015 and in Hildesheim, Germany, in March 2016. The committee is responsible for creating the concept and organizing the worship and prayer life of the Assembly, including the liturgy for the commemoration of the Reformation anniversary and producing the worship and songbook of the Twelfth Assembly.
Within the Communion Office, preparations are undertaken collectively by staff under the leadership of the General Secretary and coordinated by the Assembly Coordinator. An Assembly Office in Windhoek oversees the local preparations being undertaken by the Local Assembly Planning Committee and assists the Geneva Assembly Office in setting up the logistical and technical infrastructure of the Assembly.
In Namibia, the United Church Council of the Namibian Evangelical Lutheran Churches composed of the three Lutheran member churches appointed the Local Assembly Planning Committee. The LAPC is responsible for promoting the Assembly in Namibia and preparing the local congregations for their participation at the Assembly and the commemoration event.