Background: Patient and Public involvement (PPI) in health services research has received considerable and increasing attention both in the UK and internationally over the last 10-20 years. Although there has been a widespread promotion of PPI, those who are usually involved do not always reflect the diversity of populations. People from Black, Asian and Minority Ethnic (BAME) groups are under-represented as part of PPI in health services research. As there is limited evidence on PPI from members of BAME groups, this work will aim to: 1) understand PPI of BAME groups in health services research in terms of who, how and where they are involved and what the perceived barriers and facilitators to their involvement are and, 2) investigate health services researchers' experiences of involving or attempting to involve, people from BAME groups in a PPI capacity. This PhD uses three studies to answer these two aims. Methods: Studies one and two addressed aim one and Study three, addressed aim two. In the first Study, a systematic review of international evidence was undertaken to identify the empirical literature on BAME-PPI and, identify and describe reported factors that influence BAME-PPI in health and social care. This was followed by two qualitative studies. The first involved twenty-seven qualitative interviews with South Asian participants from community settings in North West England to understand their views and experiences of PPI and factors influencing their involvement in health services research. The second involved twenty-seven qualitative interviews with people identifying themselves as health services researchers across England to explore their views and experiences of involving people from BAME groups and factors that influence their involvement. Interview transcripts formed the data and were analysed using a constant comparison approach. Results: From the systematic review, findings suggest that the majority (forty of the forty-five) of the studies were undertaken in North America focusing on African Americans and aboriginal/indigenous populations using community-based participatory research (CBPR) approaches. Other studies were undertaken in Australia/New Zealand (n=3) and in the UK (n=2). Involvement most commonly occurred during the research design phase and least in data analysis and interpretation phases. Only eleven studies reported some of the factors that promoted or inhibited involvement. Overall, the evidence base was weak as there was limited information on the nature and content of BAME-PPI related activities with a need for further substantive development in terms of understanding factors that influence BAME involvement. There was little evidence on South Asian Involvement in a PPI capacity although people of South Asians backgrounds form the largest minority ethnic group in the UK with 33% of the BAME population identifying themselves as Asian or Asian British. These groups experience health inequalities in comparison to their White British counterparts. Therefore subsequent qualitative studies identified the themes that are central for South Asian participants: interpretations of PPI, factors that impede or facilitate PPI and motivations for PPI. For health services researchers, the central themes were: Interpretations and forms of PPI and barriers and facilitators to PPI. Conclusion: These studies provide a unique contribution to the literature on PPI in health services research by exploring the views and experiences of both researchers and South Asians. They have addressed some of the gaps in knowledge regarding barriers and facilitators to BAME-PPI. While the majority of these findings map onto existing identified issues in the wider literature focusing on BAME participation and engagement, some unique issues identified show that PPI approaches need to be tailored to the group in question. The overall paucity of evidence particularly in the UK-PPI context suggests that work is still needed to determine context-specific barriers and facilitators to BAME involvement and associated strategies to widening inclusivity in PPI in health services research. The findings reported in this thesis shed light on potential approaches researchers could employ in future studies when involving BAME contributors in health services research.