PLAIN ENGLISH SUMMARY:Researchers are expected to actively involve stakeholders (including patients, the public, health professionals, and others) in their research. Although researchers increasingly recognise that this is good practice, there is limited practical guidance about how to involve stakeholders. Systematic reviews are a research method in which international literature is brought together, using carefully designed and rigorous methods to answer a specified question about healthcare. We want to investigate how researchers have involved stakeholders in systematic reviews, and how involvement has potentially affected the quality and impact of reviews. We plan to bring this information together by searching and reviewing the literature for reports of stakeholder involvement in systematic reviews. This paper describes in detail the methods that we plan to use to do this. After carrying out comprehensive searches for literature, we will: 1. Provide an overview of identified reports, describing key information such as types of stakeholders involved, and how. 2. Pick out reports of involvement which include detailed descriptions of how researchers involved people in a systematic review and summarise the methods they used. We will consider who was involved, how people were recruited, and how the involvement was organised and managed. 3. Bring together any reports which have explored the effect, or impact, of involving stakeholders in a systematic review. We will assess the quality of these reports, and summarise their findings. Once completed, our review will be used to produce training resources aimed at helping researchers to improve ways of involving stakeholders in systematic reviews. ABSTRACT:Background There is an expectation for stakeholders (including patients, the public, health professionals, and others) to be involved in research. Researchers are increasingly recognising that it is good practice to involve stakeholders in systematic reviews. There is currently a lack of evidence about (A) how to do this and (B) the effects, or impact, of such involvement. We aim to create a map of the evidence relating to stakeholder involvement in systematic reviews, and use this evidence to address the two points above. Methods We will complete a mixed-method synthesis of the evidence, first completing a scoping review to create a broad map of evidence relating to stakeholder involvement in systematic reviews, and secondly completing two contingent syntheses. We will use a stepwise approach to searching; the initial step will include comprehensive searches of electronic databases, including CENTRAL, AMED, Embase, Medline, Cinahl and other databases, supplemented with pre-defined hand-searching and contacting authors. Two reviewers will undertake each review task (i.e., screening, data extraction) using standard systematic review processes. For the scoping review, we will include any paper, regardless of publication status or study design, which investigates, reports or discusses involvement in a systematic review. Included papers will be summarised within structured tables. Criteria for judging the focus and comprehensiveness of the description of methods of involvement will be applied, informing which papers are included within the two contingent syntheses. Synthesis A will detail the methods that have been used to involve stakeholders in systematic reviews. Papers from the scoping review that are judged to provide an adequate description of methods or approaches will be included. Details of the methods of involvement will be extracted from included papers using pre-defined headings, presented in tables and described narratively. Synthesis B will include studies that explore the effect of stakeholder involvement on the quality, relevance or impact of a systematic review, as identified from the scoping review. Study quality will be appraised, data extracted and synthesised within tables. Discussion This review should help researchers select, improve and evaluate methods of involving stakeholders in systematic reviews. Review findings will contribute to Cochrane training resources.