Frontotemporal dementia (FTD) is a progressive neurodegenerative brain condition clinically characterized by marked changes in behaviour that impact the individuals’ relationships and community participation, and present challenges for families. Family carers of individuals with FTD find apathy and disinhibition particularly challenging leading to high levels of stress and burden. Positive behaviour support (PBS) as a behaviour intervention framework has never been trialled in FTD. This pilot study examined the functional basis of apathetic and disinhibited behaviours in four FTD dyads and explored the acceptability of a PBS intervention. The PBS programme was provided by an occupational therapist in the participants’ homes. Measures collected at baseline and post-intervention (M = 3.9 months) assessed: function of behaviours, challenging behaviours, and qualitative outcomes pertaining to the acceptability of the PBS approach. PBS was an acceptable intervention for all four dyads. “Sensory” and “tangible” were the most common functions contributing to the maintenance of behaviour changes, and aspects of apathetic and disinhibited behaviours improved following intervention. This study demonstrates the acceptability and potential benefit of a PBS programme to provide support in FTD. A more rigorous trial will be an important next step in developing improved services tailored to the needs of this unique population.