Expressed emotion, burden and quality of life of relatives received attention because of the increasing interest in predicting and preventing relapse in psychotic patients; but they have subsequently acquired interest of their own as important aspects of families' psychological well-being. The study explores whether the psychological distress and illness perception of a sample of relatives of Mexican patients with psychosis can predict their levels of expressed emotion, burden and quality of life above patients' clinical and functional status. Sixty-five patient-relative dyads were interviewed. Relatives self-reported on expressed emotion, burden, quality of life, psychological distress and illness perception. Patients' clinical and functional status was rated by an interviewer. Pearson correlations and hierarchical multiple linear regressions were used for statistical analyses. Patients' functional status and relatives' psychological distress were significantly associated with expressed emotion, burden and quality of life. Patients' clinical status and relatives' illness perception were most strongly related to expressed emotion and burden. Relatives' psychological distress and illness perception dimensions predicted both burden and quality of life, over and above patients' clinical and functional status. Results underscore the relatives' need of support to overcome their own distress and concerns about the illness, for the psychological well-being of both patients and relatives.