Background: People with memory disorders often need care and help from family carers and health and social care providers. Due to the deterioration of cognitive capacity and language skills, they may be unable to convey their thoughts and care preferences to other people. As a result, their agency may become restricted. We investigated the descriptions provided by people with memory disorders and spousal carers of their influence on care in encounters with formal care providers. Methods: Qualitative thematic analysis was used to identify, analyze, and report themes that describe encounters with professionals in different social or healthcare environments. In-depth interview data were gathered from 19 spouse carers and 15 persons with memory disorders. Findings: Three themes out of four describe how people with memory disorders and their spouse carers influence formal care: Acquiescence, negotiating care decisions, and taking control. The fourth theme describes lack of influence. People with memory disorders and their spouse carers have ways to influence care, but spouse carers identified more ways of doing so. Both either accepted and followed the care guidelines by the formal carers or took control of the situation and made their own decisions. Spouse carers also sought to influence care decisions through negotiations with formal carers. When formal carers’ decisions were experienced as inconsistent or the rationale of their actions difficult to follow, the possibilities to influence care were limited. Conclusions: People with memory disorders and their family carers are often in a disadvantaged position as they lack power over the health and social care decision-making during the illness, which is often guided by structural factors. To support the agency of people with memory disorders and to promote shared decision-making, clarification of the service structure and clearer communication between the different parties involved in care are required.