Research concerning the reciprocal influence of relationships and dementia largely focuses on dyadic relationships despite evidence that whole families are affected. Furthermore, such research generally considers more common forms of dementia such as Alzheimer's disease. Behavioural variant fronto-temporal dementia (bvFTD) primarily although not exclusively affects people below the age of 65 and is distinctly different in its impact from more common forms of dementia, affecting social cognition and therefore relational functioning. We aimed to develop a detailed understanding of intergenerational family experiences of bvFTD over time. We adopted a social constructivist and pluralist approach, using Narrative Thematic Analysis and Grounded Theory. We interviewed seven families in their own homes, including the person with bvFTD, at up to three time-points every six to nine months from 2012 to 2014, resulting in 46 interviews with 19 family members. Three super-ordinate themes were identified: Theme 1: We before bvFTD: cohesive and connected – disconnected and distant; Theme 2: Challenges experienced by us; and Theme 3: Relational outcomes: a changing we – an entrenched we. Results emphasise bvFTD brought early and significant disruption to family relationships. The interplay of prior relational functioning, involving the nature of the relationship for family members, the specific impact of bvFTD on these relationships and family member's understanding of bvFTD was critical to how each family fared over the duration of the research, and the relational outcomes they experienced. These findings suggest health-care practice could enhance its support for families living with bvFTD, through the development of tailored, family-oriented approaches to assessment and practice. Such approaches are necessary to understand how families work together and identify interventions that address the family-specific challenges bvFTD brings. The provision of tailored, relational-focused and specialised information concerning the experience of living with bvFTD is needed to flexibly address families' needs and expectations.