Agency is talked about by many as something that people living with dementia lose, once they've lost much else—autonomy, identity, and privacy, among other things. While the language of loss may capture some of what transpires in dementia, it can obscure how people living with dementia and their loved ones share agency through sharing capacities for memory, language, and decision‐making. We suggest that one consequence of adopting a framework of loss is that it makes the default response to changes in agency the substitution of a family member's agency for the purported lost agency of someone living with dementia. We argue for an alternative framework in which sharing agency is recognized as a central feature of living with dementia. Building on the work of relational theorists, we argue for the value of thinking about agency in dementia as fundamentally shared, and explore potential implications for treatment, caregiver support, and building dementia‐friendly environments.