Abstract Aims. This article reports on a study of quality of life of older people with dementia, as assessed by the person with dementia, family carer and care staff. Background. People with dementia can give meaningful assessments of their quality of life, but these often differ from proxy ratings. In understanding this discrepancy, the influence of age, extent of cognitive impairment and activity limitation has been investigated. A lack of conclusive associations between quality of life ratings and these variables indicates a need for further research. Methods. Fifty-eight triads comprising the person with dementia, family carer and member of care staff from four long-term care facilities were surveyed on the Quality of Life-Alzheimer's Disease questionnaire between August and December 2007. Results. There was an important difference in the Quality of Life-Alzheimer's Disease questionnaire total mean scores between groups, with the person with dementia providing the highest ratings. Level of impairment in Activities of Daily Living had an important effect on quality of life ratings, with proxies, particularly care staff, providing lower ratings when there was greater activity limitation. This was not replicated for assessments made by the person with dementia. Age or level of cognitive impairment did not influence any ratings. Conclusion. People with dementia can give assessments of their quality of life. However, discrepancy in ratings, with greater activity limitation affecting proxy ratings but not those made by the person with dementia, indicates the importance of including both self-report and proxy measures in research and care planning.