Aim To describe family members' experiences of living with persons with neuropsychiatric symptoms (NPS) related to frontotemporal dementia (FTD). Background The majority of persons with dementia during the disease trajectory develop NPS. Persons with FTD are likely to develop greater levels of NPS than persons with other types of dementias. Research-based knowledge regarding family members' experiences of living with persons with FTD and NPS is limited. Methods Nine family members of persons with FTD were interviewed. Interviews commenced with completion of the Neuropsychiatric Inventory (NPI). Upon completion of the NPI, questions were posed from an interview guide where study participants provided in-depth information about NPS identified. Interview data were analysed using qualitative content analysis. Results Interviewed family members highlighted that persons with FTD had developed between four and eight co-existing NPS. Irritability and disinhibition were the most common NPS, with variations in severity, frequency and distress. From the interview data, two themes emerged: Living with a well-known stranger and Coping and overstepping social norms. Conclusions Living with a well-known stranger depicted a new co-existence with a loved one with changes in personality and behaviour, which were not inherent to the person or predictable any more. The presence of NPS can threaten the safety of the person with FTD and their family in real world and on social media. Support offered should focus on the person's physical and psychological needs, not on a diagnosis. Implications for practice From a health care perspective it is important to see the person with FTD and their family as unique individuals with specific needs.