Research assessing the impact of inappropriate sexual behaviour (ISB) on staff working in dementia care is circumscribed, yet studies from comparable settings indicate that ISB appears uniquely challenging, particularly to personal and cultural values. This study explored staff experiences of ISB exhibited by older adults with a dementia. Fourteen staff working within an in-patient setting were interviewed. Participants’ experiences of ISB appeared underpinned by complex social and psychological processes. Shock, embarrassment and incomprehension were prominent when ISB was initially encountered. Knowledge of dementia, familiarity with patients and social norms were important in contextualising ISB and staff often minimised its impact by construing a lack of capacity. Feelings about ISB appeared equivocal and findings suggest that the effect of ISB should be routinely considered in preparing staff who work within dementia care.