AIMS:The factors contributing to the establishment of high-quality radiotherapy services in low- and middle-income countries (LMICs) are poorly understood. The aim was to identify and describe barriers and facilitators to establishing and sustaining high-quality and accessible radiotherapy services in LMICs based on the experience of successful and unsuccessful attempts. METHODS:An exploratory-descriptive qualitative study using semistructured telephone interviews was undertaken. Purposive and snowball sampling techniques were used to recruit participants. The World Health Organization Innovative Care for Chronic Conditions Framework informed the interview guide. A constant comparative data analysis approach was adopted. FINDINGS:Seventeen participants were interviewed. Ten were working permanently in nine LMICs and seven were permanently employed in four high-income countries. Three themes were developed: committing to a vision of improving cancer care; making it happen and sustaining a safe service; and leveraging off radiotherapy to strengthen integrated cancer care. Identified barriers included lack of political leadership continuity, lack of a coordinated advocacy effort, non-Member State of the IAEA, lack of reliable epidemiological data, lack of a comprehensive budget and lack of local expertise. Facilitators identified included strong political support, vision champion, availability of a regulator, costed cancer control plan, diversified sources of funding, responsible project manager, adoption of evidence-based practice, strategic partnerships, motivation to provide patient-centered care, and availability of supportive technology. CONCLUSIONS:Assessing the level of readiness to establish and sustain a radiotherapy service is highly recommended. Future research is recommended to develop a readiness assessment tool for radiotherapy services implementation at LMICs.