This research studied the effects of a lifestyle intervention on health-related quality of life (HRQoL) and metabolic risk factors in persons with psychosis, using a longitudinal intervention design with a matched reference sample. In participants in the intervention group, scores on the EQ-VAS, which measured HRQoL, improved from 57.6 to 63.3 (SD = 17.8) (p = 0.05), and HDL cholesterol concentration increased from 1.03 to 1.11 (0.19) mmol/l. (p = 0.02). There was no significant change in body weight among participants. The results of this study indicate that a lifestyle intervention based on group meetings improves HRQoL in patients with psychosis and provides small improvements in metabolic risk factors.