PURPOSE:\ud The support needs of cancer patients vary according to the phase of their cancer journey. Recent developments in healthcare are such that the advanced cancer phase is increasingly experienced as a chronic illness phase, with consequent changes in patient support needs. Understanding these needs, and identifying areas of unmet need, can enable us to develop services that are more adequate to the task of supporting this population.\ud METHODS:\ud We conducted a systematic search of four electronic databases to identify studies examining the unmet needs of people living with advanced cancer. Relevant data were extracted and synthesised; meta-analyses were conducted to obtain pooled estimates for prevalence of needs.\ud RESULTS:\ud We identified 23 studies (4 qualitative) for inclusion. Unmet needs were identified across a broad range of domains, with greatest prevalence in informational (30-55 %), psychological (18-42 %), physical (17-48 %), and functional (17-37 %) domains. There was considerable heterogeneity amongst studies in terms of methods of assessment, coding and reporting of needs, respondent characteristics, and appraised study quality.\ud CONCLUSIONS:\ud Heterogeneity made it difficult to compare across studies and inflated confidence intervals for pooled estimates of prevalence-we need standardised and comprehensive approaches to assessment and reporting of unmet needs to further our understanding. Nonetheless, the review identified prominent needs across a range of (interacting) experiential domains. Moreover, by focussing on unmet needs for support, we were able to extrapolate potential implications for service development