Aim: The purpose of this study was to evaluate the effect of a comprehensive mobile application program in managing behavior and psychological symptoms of home‐dwelling patients with dementia in South Korea. Methods: A nonequivalent control group pretest‐posttest design was conducted. A total of 26 family caregivers participated in this study. The application program consists of understanding of dementia, interventions, communication skills, coping methods, and bulletin boards. Data collection was performed from July 9, 2018, to October 4, 2018. Family caregivers' fatigue, sleep, and burden and patients with behavioral and psychological symptoms of dementia were measured. For data analysis, descriptive statistics, independent t tests, Mann–Whitney U test, repeated measures analysis of variance, and Friedman test were used. Results: The application program offered environmental management in an intervention using communication skills and coping methods, depending on the behavioral and psychological symptom type. The results showed significant differences between the two groups in family caregivers' fatigue (F = 11.24, p =.003) and burden (χ2 = 10.55, p =.005). Conclusion: The findings showed the application program improved family caregivers' fatigue and burden. It also suggested there is a need to develop a wandering persons location program to improve family caregivers' stress and patients' behavioral problems in future studies.