OBJECTIVES Cancer patients undergoing active tumor therapy experience emotional strain and social isolation, while treatment-related side effects, immunosuppression, infection risk, and reduced mobility may limit access to psychosocial support. Although music therapy is an established component of supportive oncology care, evidence on video-based group music therapy remains limited, regarding therapeutic alliance, group cohesion, and patients' experiences. This study explored participants' experiences with a video-based online group music therapy intervention during cancer treatment. METHODS This qualitative study examined experiences with a video-based online music therapy group intervention for adults undergoing cancer treatment. Semi-structured interviews were conducted with 13 participants who completed eight weekly group sessions. Data were analyzed using qualitative content analysis following Mayring and reported in accordance with the COREQ criteria. RESULTS Analysis yielded five categories: (1) expectations and initial attitudes, (2) perceived effects and evaluation of the intervention, (3) therapeutic alliance and group cohesion, (4) experiences with the online format, and (5) anticipated longer-term effects. Participants reported that music facilitated emotional awareness, reflection, and interpersonal exchange. Therapeutic alliance and group cohesion were described as developing over the course of the intervention despite the online setting. The online format improved accessibility by overcoming geographical barriers and reducing physical demands, while reduced in-person interaction, technical issues, and limited program duration were experienced as constraints. Participants described intentions to continue using music- and mindfulness-based strategies in everyday life. CONCLUSIONS The findings suggest that therapeutic alliance, group cohesion, and relational processes can develop in video-based online group music therapy. Intervention structure, facilitation, and duration appear to play a central role in shaping participants' experiences. Video-based music therapy groups may provide a feasible psycho-oncological support option for patients who face barriers to in-person participation. CLINICAL TRIAL REGISTRATION The overarching intervention study was prospectively registered in the German Clinical Trials Register (DRKS00032339; registered 3 August 2023).
