IntroductionInequity in access to healthcare in the United Kingdom can have a profound impact on people's ability to manage their health problems. Link work interventions attempt to overcome the socioeconomic and structural barriers that perpetuate health inequalities. Link workers are typically staff members without professional clinical qualifications who support patients to bridge the gap between services. However, little is currently known about how and why link work interventions might be effective. This realist review attempts to understand the contexts and resultant mechanisms by which link work interventions affect access to community healthcare services.MethodsThe authors completed a systematic search of empirical literature in Embase, CINAHL, Medline, PsychInfo and SocIndex, as well as grey literature and CLUSTER searches. Context, mechanism and outcome (CMO) configurations were generated iteratively in consultation with an expert panel and grouped into theory areas.ResultsThirty‐one eligible manuscripts were identified, resulting in nine CMO configurations within three theory areas. These pertained to adequate time in time‐pressured systems; the importance of link workers being embedded across multiple systems; and emotional and practical support for link workers.ConclusionAlthough link work interventions are increasingly utilised across community healthcare settings, the contexts in which they operate vary considerably, triggering a range of mechanisms. The findings suggest that careful matching of resources to patient need and complexity is important. It affords link workers the time to develop relationships with patients, embed themselves in local communities and referring teams, and develop knowledge of local challenges.Patient or Public ContributionThe team included people with lived experience of mental health conditions and a carer who were involved at all stages of the review.