Family caregivers of people with substance abuse are exposed to psychological problems that diminish their life quality and satisfaction. The purpose of this study was to diagnose the efficacy of quality-of-life intervention on stress and life satisfaction of family caregivers of individuals with substance use problem. This is a randomized controlled trial conducted on 80 family caregivers of individuals with substance use problem in the process of withdrawal who were referred to a psychiatric center in southeastern Iran (2018). The intervention group received seven sessions of quality-of-life group counseling every other day based on predetermined content. Twelve weeks post-intervention, data were collected from the control and intervention groups using the Depression Anxiety and Stress Scales (DASS-21) and the Satisfaction with Life Scale (SWLS). The results were analyzed through statistical tests. After group counseling based on quality of life, the mean stress score in the family caregivers of the intervention group (11.50 ± 4.36) was significantly lower than in those of the control group (14.67 ± 4.93) (p = 0.003). Also, in the posttest, the mean score of life satisfaction in the intervention group (24.75 ± 4.28) was significantly higher than that of the control group (19.57 ± 7.33) (p = 0.001). Group counseling based on quality of life exerted a significantly positive impact on reducing the severity of stress and improving life satisfaction among family caregivers of individuals with substance use problem. Therefore, it is highly recommended that healthcare service providers incorporate this counseling approach in substance use withdrawal programs so as to increase the well-being and mental health of family caregivers.