BACKGROUND Increases in cancer survivorship negatively impact patients and family caregivers, decreasing quality of life. Previous dyadic interventions involved them as a unit and focused on their outcomes, but inconsistent results existed in influencing quality of life. OBJECTIVE To assess dyadic intervention effect on quality of life for cancer patients and family caregivers across different cancer types and intervention durations. METHODS A systematic review and meta-analysis based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). METHODS Six databases were searched from establishment until 14 January 2024. Two authors independently performed the search process, literature screening, and data extraction. The ROB version 2 and GRADE were respectively used to check the methodology and evidence quality. The data were analysed via RStudio, and intervention effects were estimated with 95% CIs and SMDs. The statistical heterogeneity was explored through the I2 statistic, P values, and Egger's test, and differences in overall effects were deemed statistically significant, having a P value < 0.05. Subgroup analysis was also conducted. RESULTS 13 RCTs with 1625 participants, published from 2005 to 2021, were included. The results demonstrated that dyadic interventions enhanced quality of life for both cancer patients and family caregivers. Subgroup analysis suggested that family-centred interventions for patients with specific cancer types, which lasted for a long period (> 6 weeks), enhanced quality of life for cancer patients and family caregivers. The evidence and methodology were of a moderate quality. CONCLUSIONS Nurses are important practitioners of culture-oriented dyadic interventions. Long-term (> 6 weeks) and family-centred dyadic interventions for patients with a specific cancer type can enhance cancer patients' and family caregivers' quality of life, along with digital intelligence approaches to promote mutual communication and strengthen family relationships, thereby optimising oncology clinical nursing and enhancing the quality of life, health, and welfare of the entire family. CONCLUSIONS Dyadic interventions emphasising the involvement of both cancer patients and family caregivers should be considered and tailored by professionals and oncology nurses to establish harmonious family relationships, improve family coping techniques and decision-making to enhance the whole family's quality of life and well-being according to their cultural contexts, and promote more efficient, targeted, and economical oncology care. No Patient or Public Contribution because all the involved participants were from existing studies, and the design, conduction, analysis, and interpretation of the data were completed by the authors in this article. BACKGROUND International Prospective Register of Systematic Reviews: CRD42024519432; https://www.crd.york.ac.uk/PROSPERO/#recordDetails.