The British NHS has continuously innovated since its inception almost 75 years ago.Innovations come in many forms and range from process innovations to advances in technology and digital enablers, which have radically changed professional practice. There are also a large volume and wide range of managerial improvement programmes and significant levels of evidence-based practice as well as clinical research. The challenge lies in determining how best to implement these innovations into existing systems so that their potential can be realised.Throughout all of these years, the locus of research activity has been on secondary care and specialist innovations. This bias has favoured clinical and professional groups who operate in highly specialised and distinctive areas of health and care provision. The majority of NHS activity, however, occurs in primary care where there is less specialisation and organisations tend to be smaller. With more limited financial resources, general practices face significant challenges in their attempts to embrace the latest innovations for the benefit of patients and local communities. This research addresses the determinants (enablers and inhibitors) that relate to the adoption of innovation by primary care organisations, building theory and redressing the imbalance in research activities.While some models of implementation already exist, they have been drawn from the field of secondary care. Having exposed a gap, this research responds by developing a framework that specifically focuses on the implementation of innovation, improvement and evidence based practice (known as ‘EBP’) in primary care.The study takes a realist pragmatic approach to understanding the enablers and inhibitors of the implementation of innovation, improvement and EBP into primary care. The research has been conducted by means of several distinct phases. This includes an initial conceptual model, drawn from a review of the existing academic literature, followed by a qualitative phase of expert interviews with purposively selected informants as well as the development of an empirical model. The researcher also created a questionnaire which was sent to experts from various parts of the Welsh NHS innovation ecosystem. The research study contributes much to our understanding of innovation in primary care and has resulted in a final and tested model of the innovation, improvement and EBP implementation that is in operation in Wales. The research finds many failings in the current system, which are preventing the seamless migration of promising innovations and advances in care into the primary care sector. These inhibitors include a lack of trust between the actors within the system, the imposition of national directives – without any form of support to the general practices – and a lack of competence in the form of variable staff competence in general practitioners’ surgeries.The research concludes that the determinants identified and the poor levels of trust and joint participation between providers, commissioners and government are preventing a collaborative systems approach. Primary care in the Welsh NHS, therefore, is currently unable – as a system – to create a critical mass of general practices that all use similar and interoperable innovations. Without such sharing of innovation, improvement and EBP, and without addressing the way in which the stakeholders of the Welsh NHS interact, it is unlikely that meaningful progress will be made across all general practices in Wales.