Background and Objectives. Medication adherence is the main determinant in the successful treatment of tuberculosis. The identification of the factors related to medication adherence is necessary to carry out appropriate interventions and to ameliorate tuberculosis control. Although medication nonadherence is more common in elderly tuberculosis patients, few studies have investigated the factors related to medication adherence in this age group, and there is no specific study in this field. Therefore, the objective of this study was explaining the factors related to medication adherence based on the healthcare professionals, elderly tuberculosis patients, and their caregivers’ experiences. Methods. This qualitative study was conducted in two phases, using an integrative literature review and individual interviews. Studies were gathered without time restriction from MEDLINE databases, Institute for Scientific Information (ISI), Google Scholar, Scopus, and EMBASE, as well as national databases, including Scientific Information Database and Magiran. The findings of 38 studies that met the inclusion criteria were analyzed through the conventional content analysis method based on the ecological approach. After reviewing and forming the data matrix, purposive sampling was performed among healthcare professionals, elderly tuberculosis patients aged 60 and over, and family caregivers of elderly patients to conduct individual interviews. Data obtained from 20 interviews were analyzed using the directed content analysis method. After coding, the data from individual interviews were entered based on similarity and difference in the categories of data matrix obtained from the literature review. Results. In general, the aforementioned codes were placed in four main categories, including individual factors (i.e., biological factors, affective-emotional factors, behavioral factors, cognitive factors, tuberculosis-related factors, and economic factors), interpersonal factors (i.e., patient’s relationship with treatment team and family-related factors), factors related to healthcare service provider centers (i.e., medical centers’ facilities and capacity building in healthcare service provider), and extraorganizational factors (i.e., social factors and health policymaking). Conclusion. The results of this study showed that medication adherence in elderly patients with tuberculosis was a complex and multidimensional phenomenon. Therefore, society, policymakers, and healthcare providers should scrutinize the factors affecting medication adherence in this group of patients to plan and implement more effective interventions.