The global burden of cancer falls heavily on low- and middle-income countries (LMICs), where there are critical gaps in the provision of supportive care services, which leaves many cancer patients in these settings feeling overwhelmed and unable to manage the psychological effects associated with a cancer diagnosis and the ensuing treatment. In addressing these gaps, we adapted a widely replicated cancer peer mentoring model in the USA to the Viet Nam context. Using the Cultural Adaptation Framework, we examined cultural characteristics affecting three key domains—cognitive information processing, affective-motivational, and environmental—to inform the types of adaptations that are made to the program. We highlight here the major findings in the three domains and the adaptations made. This illustration can inform future efforts to adapt successful programs to different cultural contexts, ensuring that cancer psychosocial programs and activities are acceptable and appropriate to the culture, health system, and resources of the local community and setting.