Introduction The primary functions of peer reviewers are poorly defined. Thus far no body of literature has systematically identified the roles and tasks of peer reviewers of biomedical journals. A clear establishment of these can lead to improvements in the peer review process. The purpose of this scoping review is to determine what is known on the roles and tasks of peer reviewers.

Methods We will use the methodological framework first proposed by Arksey and O’Malley and subsequently adapted by Levac et al and the Joanna Briggs Institute. The scoping review will include all study designs, as well as editorials, commentaries and grey literature. The following eight electronic databases will be searched (from inception to May 2017): Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Educational Resources Information Center, EMBASE, MEDLINE, PsycINFO, Scopus and Web of Science. Two reviewers will use inclusion and exclusion criteria based on the ‘Population–Concept–Context’ framework to independently screen titles and abstracts of articles considered for inclusion. Full-text screening of relevant eligible articles will also be carried out by two reviewers. The search strategy for grey literature will include searching in websites of existing networks, biomedical journal publishers and organisations that offer resources for peer reviewers. In addition we will review journal guidelines to peer reviewers on how to perform the manuscript review. Journals will be selected using the 2016 journal impact factor. We will identify and assess the top five, middle five and lowest-ranking five journals across all medical specialties.

Ethics and dissemination This scoping review will undertake a secondary analysis of data already collected and does not require ethical approval. The results will be disseminated through journals and conferences targeting stakeholders involved in peer review in biomedical research.