Objective To describe patterns of use of the available Government-subsidised mental health services among people living in Australian residential aged care facilities. Methods A retrospective population-based trend analysis was conducted, including all non-Indigenous people living in an Australian facility between 2012 and 2017. Adjusted incidence proportions and trends were estimated for four groups of mental health services. Results The use of Medicare-subsidised mental health services was very low overall. The proportion of residents who accessed primary care mental health services increased from 1.3% in 2012/2013 to 2.4% in 2016/2017, while psychiatry service use increased from 1.9 to 2.3%. Claims for clinical psychology increased from 0.18 to 0.26%, and claims for a registered psychologist, occupational therapist or social worker rose from 0.45 to 1.2%. People with dementia were less likely than people without dementia to access all services aside from psychiatry services. Conclusions Less than 3% of residents accessed funding subsidies for mental health services and people with dementia experienced pronounced barriers to service access. Mental health care is a pillar of the publicly-funded health system in Australia, and low use of these services among aged care residents indicates a need for organisational and policy changes to improve access.