Introduction: Families of patients with low consciousness have an important role in supporting them and should acquire the necessary capability for patient care. Objective: This study aimed to examine the effect of family-centered interventions on the self-efficacy of the families of patients admitted to the intensive care units. Materials and Methods: This research was a randomized clinical trial with a pretest-posttest design conducted in intensive care units of hospitals in Khorram abad City, Iran, in 2019-2020. Seventy family members of patients were selected by convenience sampling and were assigned to the intervention (n=28) and control (n=28) groups by stratified random blocks. The study data were collected through the self-efficacy questionnaire and Hospital Anxiety and Depression Scale. The intervention was carried out using a family-centered model. The collected data were analyzed using the statistical tests of the Chi-square, independent t-test, and paired t-test. Also, the generalized linear model was used to compare changes in self-efficacy scores of the two study groups after adjusting demographic, anxiety, and depression variables. Results: Data analysis showed that most samples were male (53.8%) with a mean age of 38.15±8.68 years. The results showed a significant difference in the mean scores of self-efficacy, anxiety, and depression between the intervention and control groups (P=0.001). The intervention significantly increased the Mean±SD of caregivers’ self-efficacy (40.14±14.35, P=0.001) in the intervention group. The results showed that the self-efficacy mean score of the intervention group was 36 scores higher than the caregivers’ self-efficacy of the control group (95% CI; 20.6-51.4, P=0.028). Conclusion: The participation of family members of patients with low consciousness in the care of the patients in the intensive care unit has an effective role in the self-efficacy of caregivers of these patients.