Background <p>Global cancer cases are predicted to rise to 35 million by 2050 and survival rates are also increasing, meaning the number of patients experiencing late effects from their cancer treatment is expected to rise. Post-treatment side effects can present physically, psychologically, and functionally. These complications can include peripheral neuropathies, fatigue, cognitive or sexual difficulties, and heightened anxiety or depression.</p> <p>A wide range of online interventions have been developed as treatment and support tools for cancer patients following treatment, including self-directed or therapy-assisted programs, symptom-reporting applications and education tools. Research to examine the effectiveness of online interventions for the management of late effects has shown these interventions to have a positive impact on outcomes such as managing fatigue, depression, and overall quality of life.</p> <p>The aim of this study is to systematically identify, review and synthesise the qualitative experiences of patients with cancer using online interventions for managing late effects post-cancer treatment in order to further inform the design and implementation.</p> Methods <p>A comprehensive search strategy has been developed to identify studies across six different databases (MEDLINE, EMBASE, EMCARE, PSYCHINFO, CINAHL and The Cochrane Library). Studies will be screened and selected by two independent reviewers. The inclusion criterion includes peer-reviewed qualitative or mixed-methods studies, published on any date, with patients over the age of 18, in any geographical location or setting, and written in English. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) diagram will be developed to show the screening and selection process. Once included studies have been identified, Thomas and Harden’s (2008) three stages of thematic synthesis will be followed by two reviewers to generate analytical themes.</p> Discussion <p>By reviewing patients’ experience of using online interventions to help with late effects of cancer and its treatment, we hope to be able to provide some guidance for those developing and implementing these interventions into care, to maximise the benefit for patients.</p> Systematic review registration <p>PROSPERO (Reference CRD42025619614).</p>