The accreditation program is addressing the quality of performance of primary health care (PHC) facilities, within the Health Sector Reform Domain. This study aims to reach learned lessons to suggest recommendations for sustainability of quality PHC services through accreditation program. The study is a health system research that used quasi-experimental/ time series analysis- test and control group design. Both quantitative and qualitative data were collected. In-depth interviews and FGDs were done with the Ministry of Health (MOH)-HQ staff, and the staff members at the health district level as well as the service providers at the accredited PHC facilities. At the PHC facilities levels, operations research was done to assess the trend in the quality standards, PHC services output, and client satisfaction in the accredited rural family health units (ARFHUs) versus non-accredited rural health units (NRHUs). Findings of the study showed the presence of potentials for sustainability of quality PHC services through accreditation program due to political and institutional support. However, there are challenges for financial and demand sustainability. At the operational-health facility level, the articulation of accreditation with different policies related to family medicine, incentives, and cost-sharing as well as the dual implementation of vertical and family medicine programs across PHC facilities within the same district limit achievement of intended improvement in the quality of PHC services through accreditation program. The study recommended continuous political and financial support as well as community involvement as partners in the accreditation of PHC facilities.