The biopsychosocial challenges make females more prone to experiencing mental problems that can lead to extensive repercussions, affecting multiple generations cause of their significant roles in a family and society. However, mental health problems in Indonesia are still not handled optimally and the expenses for their medical care are not inexpensive. It’s important to explore factors that influence mental health to reduce the costs. So, this study aims to identify the influences of age differences and self-concept on females’ mental health in the general population of Indonesian adults. Methods: The study employed cross-sectional research, utilizing an uncontrolled quota sampling method and collecting data via the online survey. Results: Mental health can be predicted based on the self-concept (p < .001) and age differences (p < .01) of Indonesian females. Females with a significant problem of mental health are 0.76 times less likely to have high self-concept than moderate self-concept, whereas females with no significant problem of mental health are 0.96 times less likely to be found in the young adult group than in the middle year group. Conclusion: Self-concept plays one of the significant factors in shaping the mental health of adult females in Indonesia, and young adult females are the more vulnerable to mental problems. Further research about the self-concept enhancement implementation related to reducing mental treatment costs is needed.