Background. HIV remains a major public health challenge in Zambia. The roll-out of antiretroviral treatment (ART) has engendered new challenges in retention in care. Objective. To conceptualise the factors affecting retention in care of ART patients at three primary healthcare facilities using the ecological framework. Method. Qualitative data were collected through in-depth interviews with 45 ART patients and three focus group discussions with 20 healthcare providers from three primary healthcare facilities in Kabwe district, Zambia, and subjected to thematic content analysis. Results. Individual level barriers to retention in care included side effects, gaining weight, belief in faith healing, and use of herbal remedies and alcohol. Interpersonal barriers such as stigma and nondisclosure of HIV status were reported. At the institutional level, inadequate space in the clinic, long waiting times, long travel distances, and shortage of third-line drugs presented barriers to retention in care. Food shortages and patient mobility were reported as community barriers to retention in care. Conclusion. The ecological framework conceptualises the complex and dynamic factors affecting retention in ART care and highlights the need for multifaceted interventions that combine health education, disease management, and opportunities for income generation in a socially responsive and accountable environment.