This thesis considers the various church building schemes that took place in Glasgow during the early nineteenth century, focussing upon one particular model – that of church extension – to examine the way in which the Established Church of Scotland negotiated a space materially and culturally within the rapidly shifting socio-spatial dynamics of a city in the midst of processes of urbanisation and industrialisation. In so doing, the study asks what such schemes reveal of the Church’s understanding of both the city and its own role within society. The arguments used to persuade influential actors within the city to support the cause of church building are examined, and it is claimed that these arguments both drew upon and reiterated a series of claims that C. Brown has identified as belonging to a discourse of the ‘unholy city’. The material plans of church extension are next considered, detailing the mechanisms by which it was thought to work and the role of social élites in its establishment. It is claimed that, while clearly in keeping with earlier church-building plans, church extension was fundamentally different in concentrating upon churches not as means of accommodating worshippers but as centre points of a mechanism for evangelism, capable of impacting upon the manners and morals of wider society. Attention is drawn to the key influence of the Reverend Thomas Chalmers in the creation and application this model. Finally, the impacts that this was designed to have upon the city are considered, and used as a means of gaining insight into the shape of society sought by proponents of church extension. The thesis concludes by suggesting that while church extension can be interpreted critically as a tool of the Establishment, it is better conceived as a form of evangelism in which social improvement was a fundamental part, inseparable from the movement’s spiritual aspirations. Thus, it argues for the importance of understanding the Church as a religious community whose task is to engage theologically with society, and as a collection of individuals who are each a part of the very society upon which they seek to impact.