The job satisfaction of live-in foreign domestic helpers (FDHs) may influence their caring motivation and the quality of care they provide, which may in turn affect the health status of care recipients. This study identifies the factors affecting job satisfaction of FDHs caring for people with dementia in Hong Kong, focusing especially on the role of FDHs' adaptation status, job self-efficacy and care recipients' situation. A total of 152 FDHs taking care of people with dementia were recruited from 6 day care centres for elderly people in Hong Kong when they attended with their care recipients. Data were collected from February to August 2011 and the response rate was 95%. Participants completed questionnaires which included measures of care recipients' dementia severity and disruptive behaviours, FDHs' demographic factors, personal adaptation status, caregiving self-efficacy and job satisfaction. Hierarchical regression analysis was conducted to analyse the data. The results showed that longer stay in Hong Kong, better fluency in Cantonese (local dialect), greater satisfaction in living conditions, higher caregiving self-efficacy and less disruptive behaviour of care recipients were independently associated with stronger job satisfaction in FDHs looking after people with dementia. On the basis of these findings, we would suggest that employers should consider helpers who have been in Hong Kong for a longer period of time and speak fluent Cantonese, and have previous experience of taking care of people with dementia. In addition, FDHs caring for people with dementia may benefit from carer training which improves their self-efficacy in dementia care.