Abstract Background Older people have complex health needs, with the inter-play between physical and mental health being a prominent issue. The ageing population has resulted in a large proportion of older people living with co-occurring physical and mental health disorders, which can prove challenging to manage simultaneously, particularly for serious mental illness. The aim of this systematic review was to explore models of integrated physical-mental health care available for older people, and whether these result in improved health outcomes. Sources of heterogeneity in the current evidence base alongside limitations were also explored. Methods Medline, Embase, CINAHL, PsycINFO and Scopus were searched with a predefined search strategy, generating 5257 articles. Studies were suitable for inclusion where an integrated physical-mental health care service model was utilised in a population of older people (aged >60 years) with a mental health diagnosis and at least one concomitant physical health condition requiring physical health care input. All studies were quality assessed for risk of bias and results were synthesised narratively. Results Ten studies met the inclusion criteria. All studies incorporated service models involving integrated and/or multidisciplinary care. These included joint medical-mental health wards as well as the implementation of multidisciplinary teams in hospital and care facilities. Overall, this enhanced the quality of care for elderly patients with benefits including but not limited to, enhanced patient experience, the expansion of multidisciplinary team practice, improved management of illness, and timely intervention. Conclusions Multidisciplinary and integrated care resulted in improvement of a range of health outcomes for older people with combined physical and mental health needs. Larger and more robust studies are needed to explore the development of these service models further, with cost-effectiveness analyses.