Background <p>Chronic fatigue, with or without an identified underlying cause, can severely restrict social participation, education, employment, and daily activities, often leading to long-term disability. In parallel with the health challenges, many affected individuals also seek support from social security services. While cross-sectoral collaboration between healthcare and social security service in managing chronic conditions is increasingly studied, little is known about such collaboration for patients with chronic fatigue. The aim of this study was therefore to investigate the experiences of patients with chronic fatigue of unclarified cause and social security supervisors regarding cross-sectoral collaboration between healthcare and social security services in Norway, particularly through collaborative meetings initiated by specialist healthcare service.</p> Methods <p>A qualitative study was conducted using semi-structured individual interviews with nine patients and five social security supervisors who had participated in at least one collaborative meeting initiated by a tertiary care pain clinic at which the patients were referred to for a multidisciplinary examination. The meetings were part of a proposed care pathway for patients with chronic fatigue of unclarified cause and involved general practitioners, specialist healthcare providers, and social security supervisors. The data was analyzed using thematic analysis.</p> Results <p>It was found that the informants experienced pre-existing relationships with social security supervisors influenced the quality of collaboration. Some had not had any contact before the first collaborative meeting. The collaborative meetings varied in depth, from basic information sharing to meaningful dialogue and planning. The meeting structure, timing of participation, and digital format affected engagement and flow. The follow-up processes were often unclear, with varying expectations about responsibilities. While informants generally valued the meetings, they emphasized that effective collaboration required continuity, preparation, and sustained engagement beyond the meeting.</p> Conclusion <p>Collaborative meetings between healthcare and social security service were perceived as beneficial for managing complex cases of chronic fatigue. However, their effectiveness is perceived to depend on relational continuity, inclusive dialogue, and clear follow-up procedures. Structural adjustments, such as improved preparation, consistent supervisory relationships, and facilitation of shared decision-making, are suggested as actions to enhance the collaborative process and ensure person-centered cross-sectoral support for this patient group.</p>