Background/Aim: Limited attention has been given to informal carers supporting older adults living with mental health conditions. With increasing numbers of older adults receiving in-home aged care reporting mental health concerns, more carers are navigating complex and often intersecting roles. They can experience dual stigma associated with both mental illness and aged care, which can be internalised and impact carer wellbeing. This study aims to explore informal carers’ lived experiences of stigma and its impact on their wellbeing, access to support and engagement with services. Methods: A qualitative approach was used to capture lived experiences of informal carers supporting older adults with mental health conditions receiving in-home aged care. Sixty-nine carers from Australia, the United States and the United Kingdom completed open-ended surveys, with interviews underway with Australian carers. A typology of stigmatising discourses in aged care (Manchha et al., 2023) guided analysis, alongside thematic analysis to examine impact of stigma on carers. Results: Carers often felt dismissed and overlooked as they supported older adults with mental health conditions at home. They recalled encountering stereotypes that oversimplified or devalued caregiving associated with aged care and/or mental health. Carers also reported that these stigmatising experiences contributed to emotional strain and hidden costs of providing care including discrimination. Conclusions/Implications: This study provides a framework for understanding stigma in informal aged mental health caregiving contexts. The potential for the findings to inform interventions to highlight carer experiences and challenge misconceptions will be discussed.