Patient involvement is being encouraged throughout the development lifecycle of new medicines and devices. Many stakeholders (eg, patients, carers, regulators, payers, drug and device companies) have welcomed patient involvement as an important and fundamental change in the development lifecycle, and have promoted the potential benefits that meaningful, transparent, and ethical interactions with patients could bring. As with any change, however, research should be conducted to ensure the potential benefits and harms of patient involvement are understood, and that evidence-based best practices can be identified. Compared with research on patient involvement in the clinical trial process, there appears to have been relatively limited research on patient involvement in the peer-reviewed publication process. Publications can affect patient care and we have shown that patients are engaging with the peer-reviewed literature. Consistent with this interest from patients, medical journals are striving to facilitate greater patient involvement in the peer-reviewed publication ecosystem (eg, as authors, peer-reviewers, readers). The extent of published evidence on patient involvement in peer-reviewed publications, however, is not known. In addition to sharing clinical trial results through the peer-reviewed publications, results can also be shared through clinical trial results summaries. The forthcoming regulatory requirement in Europe to provide plain-language clinical trial results summaries has driven strong interest in this method of results sharing. The extent of published evidence on patient involvement in clinical trial results summaries, however, is not known. The systematic literature review is directed toward audiences who want to know the size and quality of the evidence base that exists to guide patient involvement in peer-reviewed publications and clinical trial results summaries.