This report presents the results of the scoping literature review conducted by the Knowledge and Support Hub (KSH) "Widening Participation" of the INSPIRE project. The KSH "Widening Participation" aims to describe and understand the multiple organisational pathways in the development of gender equality that are rooted in local knowledge and circumstances. In order to provide the KSH with the relevant background for its work, this report maps the existing knowledge regarding gender equality policies, particularly in the form of Gender Equality Plans (GEPs), and their development in Research & Innovation (R&I) organisations in "Widening countries" as defined by the European Commission in the Horizon Europe programme. Being critical of the term "Widening countries," we explain its meaning in the introduction to this report and the reasons for using it as an operational term. We conducted a scoping literature review using two approaches: a database search of English-language literature (a top-down approach) and questionnaires to national experts (a bottom-up approach). This allowed us to map the available data on the development and implementation of GEPs at the organisational level in Research Performing Organizations (RPOs) and Research Funding Organizations (RFOs) in the selected countries. From the 3,618 documents identified in five databases (Web of Science, Scopus, Google Scholar, EBSCO, JSTOR), we selected 60 for review and included 88 of the 133 documents suggested by national experts in the literature review. While journal articles are the most numerous type of literature in both samples, reports are much more prevalent in the literature suggested by the national experts. Although the timeframe of the search was 2012-2023, the majority had been published in the last 5 years. The coverage of country cases in the literature is only balanced when the two approaches are combined.