Yes / . Improving quality of life (QOL) for people with dementia is a priority. In care homes, we often rely on proxy ratings from staff and family but we do not know if, or how, they differ in care homes. Methods. We compared 1056 pairs of staff and family DEMQOL-Proxy ratings from 86 care homes across England. We explored factors associated with ratings quantitatively using multilevel modelling and, qualitatively, through thematic analysis of 12 staff and 12 relative interviews. Results. Staff and family ratings were weakly correlated (ρs = 0.35). Median staff scores were higher than family’s (104 v. 101; p < 0.001). Family were more likely than staff to rate resident QOL as ‘Poor’ (χ2 = 55.91, p < 0.001). Staff and family rated QOL higher when residents had fewer neuropsychiatric symptoms and severe dementia. Staff rated QOL higher in homes with lower staff:resident ratios and when staff were native English speakers. Family rated QOL higher when the resident had spent longer living in the care home and was a native English. Spouses rated residents’ QOL higher than other relatives. Qualitative results suggest differences arise because staff felt good care provided high QOL but families compared the present to the past. Family judgements centre on loss and are complicated by decisions about care home placement and their understandings of dementia. Conclusion. Proxy reports differ systematically between staff and family. Reports are influenced by the rater:staff and family may conceptualise QOL differently / This research was supported by the UK Economic and Social Research Council and the National Institute of Health Research Grant number NIHR/ESRC (S.R., P.R, L.M., G.L., C.C., S.C., ES/L 001780/1); the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care North Thames at Bart’s Health NHS Trust (SR, PP, GL); the UCLH NIHR Biomedical Research Centre (GL, CC); and the Johns Hopkins Alzheimer’s Disease Research Center (C.L., P50AG005146, PI: Albert).