Quality of life among Hong Kong's family dementia caregivers is a current heightened public health concern. This was one of the first East Asian studies to examine the role of family expressed emotion (EE) in the negative caregiver outcomes associated with dementia caregiving. EE comprises overinvolved and critical communications in families of people with mental illness. In this research, caregiver EE was evaluated as a mediator of the relationship between behavioral and psychological problems associated with dementia (BPSD) and negative caregiver outcomes. Participants were 89 Hong Kong family caregivers (79% female, 84% married, 43% >50 years of age) of people with diagnosed dementia, recruited from elder day care centers. Caregivers completed the Neuropsychiatric Inventory (NPI), Cohen Mansfield Agitation Inventory (CMAI), Level of Expressed Emotion scale (LEE), Zarit Burden Interview, and Center for Epidemiological Studies Depression Scale (CES-D). Agitation, delusions, hallucinations, aggression and irritability were BPSD most associated with caregiver burden and depression. EE significantly mediated the BPSD-negative caregiver outcome relationship. Among EE subscales, intrusiveness was significantly more common and less associated with negative caregiver outcomes. Caregiving hours, low family support, and religious nonaffiliation were associated with EE and poorer caregiver outcomes. The negative impact of BPSD on dementia caregivers in Hong Kong is influenced by EE. Higher scores on EE intrusiveness may be partly accounted for by filial piety, a strong sense of family responsibility characterized by high attentiveness to elderly family members. As EE is a potentially modifiable factor, interventions are considered.