Purpose: The Ethiopian Ministry of Health has integrated mental health services into the community health service, but it has not yet been implemented. Therefore, this study aimed to explore the barriers and facilitators of mental health service implementation in the Ethiopian community health program. Methods: A qualitative case study was conducted in the Ethiopian primary health care system in 2019. We have conducted about eight key informant interviews with policymakers, service managers, and service providers. The interviews were tape-recorded, transcribed, translated, and analyzed manually using the World Health Organization building blocks framework. Results: The Health Ministry of Ethiopia has recently included mental health services into the health extension package but not yet implemented as part of integrated services. The identified barriers were low political commitment, shortage of resources, non-functional referral system, lack of interest from private health service organizations, attitudinal problems from both the society and service providers, and lack of consistent reporting system of the mental health problems. However, the well-designed primary health care system, trained health extension workers, changing political commitment and attitude of the community could facilitate the mental health service implementation. Conclusion: A series of activities are expected, especially from the healthcare system managers to implement, follow, and evaluate mental health services implementation at the health extension programs.