This thesis develops a pentecostal ecclesiology using the structure of networks that leads to a fresh approach to contextualisation. It addresses the neglect in pentecostal scholarship of church structures beyond the congregation and of critical approaches to contextualisation. The pentecostal systematic methodology of Amos Yong is utilized, based on the synthesis of discerned experience (Spirit), biblical studies (Word) and the traditions of systematic and mission theology (Community). A trinitarian understanding of networks is developed and linked with an approach to the catholicity of the church that has a common essence and mission movement. This is shaped by the missionary nature of pentecostalism and rooted in an understanding of a church marked by Spirit baptism. The character of networks is defined in terms of partnership, a term with a rich mission understanding and seen also in the pentecostal tradition. A three-fold approach to contextualisation arises from the overlap between networks within and outside the church which is based on hospitality. Significantly, this thesis is the first in pentecostal ecclesiology to utilise a pentecostal methodology, to focus on structural and contextual issues and to develop a trinitarian network ecclesiology. It provides a fresh approach to catholicity, Spirit baptism, partnership and contextualisation.