In environments characterised by complex structures and processes, universities rely on co-operation and goodwill between staff to function effectively, underpinned by good service quality. However, there is a lack of research on relationship quality in internal service settings and on the role support staff play in the development and enhancement of these relationships. This research aims to address this gap by examining the dynamics of university support staff relationships and their contribution to institutional performance, by analysing the link between relationship quality and service quality. Findings from a qualitative study with 50 staff in three UK universities reveal the ways in which interpersonal relationships can enhance or constrain internal service quality, with consequences at individual and organisational levels. The degree of co-operation encountered within a relationship influences how value co-creation, trust and reciprocity are experienced, with effects on job performance, motivation and commitment of staff.