This thesis considers the question of socio-cultural encounters and conviviality in the context of urban retail marketplaces. It elaborates on the concept of 'conviviality' through two case studies in Greater Manchester, UK. With a focus on town centre marketplaces, this thesis considers what underpins conviviality across three elements: physical and spatial ordering, socio-cultural structure, and management and local governance. In the study of the first element, the role of the built environment and physical dimensions of place is considered in shaping encounter. The social domains of encounter are studied in more depth to explore the second element. And the final element is studied to understand the role of management bodies in shaping and mediating encounter. Marketplaces as a type of micro-public have always been much more than places of economic exchange. As flexible spatial and temporal assemblages, they can provide and provoke vivid and inclusive public spaces. However, their role in the urban fabric has been challenged by the forces of changing shopping habits, a declining economic situation of the high street, and changing urban demographics and cultural composition. While a growing body of literature explores the changing position of marketplaces, there is a gap in the exploration of their social composition, and their capacity to provide a socio-spatial expression of multicultural conviviality. The findings of this research highlight that marketplaces are sites of plural, heterogeneous and distributed practices, identities and cultures that accommodate casual relationships. Based on empirical findings in Bolton and Tommyfield (Oldham) marketplaces, this research concludes that social encounters as means of fulfilling the need for urban social experience should be mediated as well as acknowledged. Therefore, the aim of conviviality and socio-cultural understanding would not be achieved without; first, understanding the mundane practices and social encounters of marketplaces and then, inculcation and facilitation of them by the relevant authorities. This study argues that it is important to maintain the role of marketplaces in the urban public realm, as they have the spatial and social potential to contribute to the social regeneration of cities and communities. This research makes an original contribution to knowledge in terms of (1) developing wider theoretical debates about social encounter and diversity, (2) highlighting the changing role of marketplaces within the wider realm of public spaces and local governance and (3) contributing to the development of a new methodological approach to study social encounters in urban micro-publics.