BackgroundLoneliness has received considerable attention in recent years, but has seldom been investigated through a gendered lens. This review aims to critically summarise research substantively related to men and loneliness.MethodA critical interpretive synthesis, incorporating a pre-defined search strategy, was employed to analyse a broad variety of data. The searches were conducted in July 2019, across seven databases: MEDLINE; PsycINFO; Scopus, ASSIA, SSCI; Sociological Abstracts; and Social Policy and Practice. Included studies were written in English, conducted in high income nations in Western Europe, North America, and Australasia, with no date limitations. Qualitative studies required a substantive focus on sex/men or gender/masculinities and loneliness, and quantitative studies either an explicit focus on sex differences in loneliness, or data substantially relevant to loneliness and men. Seventy-nine studies met the inclusion criteria.ResultsSeven ‘synthetic constructs’ were built: i) men’s loneliness appears more associated with their social network; ii) men may be less emotionally forthright, thus both less inclined to discuss loneliness and less likely to form meaningful relationships; iii) romantic relationships may be more important for preventing loneliness in men; iv) different measurements of loneliness do not show the same sex differences in the prevalence of loneliness; v) lonely men may be more likely to engage in risky/unhealthy behaviour; vi) feeling/being ‘insufficiently masculine’ can result in loneliness; and vii) intersections of identity facilitate different gendered results.ConclusionThese constructs offer a framework that can help inform interventions aimed at preventing/alleviating loneliness in men, and a foundation for future research. Overcoming men’s emotional reticence, and facilitating better quality social networks, appeared critical goals for interventions. Men’s emotional reticence may constitute both a barrier to discussing loneliness, and to forming loneliness preventing relationships. It also appeared to be characterised either by the construction of a masculine persona, or a fear of the repercussions for initiating intimate conversation. When attempting to ascertain whether a man is lonely, acknowledging gendered variation in survey responses is required. However, it is unclear how generalisable these ‘synthetic constructs’ are, and their potential inter-relatedness requires further research.