Background: Caregiving to patients with epilepsy (PWE) is often very stressful for family caregivers and puts a heavy caregiver burden (CB) on them. The aim of this study was to evaluate the effects of Fordyce's fourteen Fundamentals for Happiness Program on happiness and CB among the family caregivers of PWE. Methods: This randomized controlled trial was conducted on seventy family caregivers of PWE. Participants were purposively recruited from the Comprehensive Health Center in Shahrekord, Iran, and randomly allocated to either an intervention or a control group. Participants in the control group received conventional health-related educations in four one-hour group sessions, while participants in the intervention group received the Fordyce's fourteen Fundamentals for Happiness Program in eight one-hour group sessions. Happiness and CB in both groups were assessed at three time points, namely before, immediately after, and two months after the intervention. Data were analyzed using the SPSS program (v. 18.0). Findings: There were no significant differences between the control and the intervention groups regarding participants' demographic characteristics and their pretest mean scores of happiness and CB (P > 0.05). The mean scores of happiness and CB in the control group did not significantly change (P > 0.05), while the mean score of happiness significantly increased and the mean score of CB significantly decreased in the intervention group across the three measurement time points (P < 0.05). Consequently, the mean score of happiness in the intervention group was significantly greater than the control group and the mean score of CB in the intervention group was significantly less than the control group at both posttests (P < 0.01). Conclusion: The Fordyce's fourteen Fundamentals for Happiness Program is effective in significantly increasing happiness and reducing CB among the family caregivers of PWE. Healthcare providers and policy makers can use this program to reduce problems among these family caregivers.