Introduction Relational aspects of the hospital workplace impact on quality of care, but are under-theorised. In efforts to improve the quality of neonatal care in resource-constrained Kenyan hospitals, there is need to better understand how relational systems and structures operate, including the role of senior nurses. The aim of this DPhil is to examine social ties between healthcare staff, and how these influence the workplace and delivery of neonatal care in Kenya.Methods The core research is a realist evaluation, conducted in two urban hospitals in Kenya. Mixed methods data were collected using non-participant observations, in-depth interviews and social network analysis. Programme theory was abstracted from explanatory context-mechanism-outcome configurations (CMOCs), and sense-checked with stakeholders. An initial programme theory (IPT) from realist synthesis, informed the realist evaluation, and a scoping review identified candidate relational interventions.Results The abstracted GELLE Framework is a middle-range programme theory explaining how, why, for whom and in what context, the social ties of staff influence quality of care, using five domains: 1) Grouping: who individuals consider to be their peers and trusted colleagues, 2) Empowering: aspects of formality and structure which influence the ability of specific individuals to act, 3) Leading: how leadership influences relational culture, 4) Learning: how learners can be supported to become competent professionals, and 5) Equipping: how physical order influences relational processes.Discussion This thesis contributes theoretical clarity to the relational workplace. It explains how duality of relational systems and structure operates, and thus how reproduction and transformation can occur, and the influence of senior nurses. The utility of the GELLE Framework is proposed as: a reflective tool, a guide for interventions, and a catalyst for further research and public engagement.The findings illuminate possibilities for influencing deep-rooted, “visible, invisible”, social phenomena in healthcare, such as norms, values, power and culture.