Background Truth-telling in health care is about providing patients with accurate information about their diagnoses and prognoses to enable them to make decisions that can benefit their overall health. Physicians worldwide, especially in the United Kingdom (U.K.) and the United States (U.S.), openly share such medical information. Bangladesh, however, is a Muslim-majority society with different social norms than Western societies. Therefore, we examined whether Muslim culture supports truth disclosure for patients, particularly how and to what extent medical information about life-threatening (...) diseases is provided to patients in Bangladesh. Methods This was a phenomenological qualitative study. We conducted thirty in-depth interviews with clinicians, nurses, patients and their relatives at Shaheed Suhrawardy Medical College Hospital in Dhaka, Bangladesh. We also used observations to explore interactions between patients, families and healthcare professionals regarding their involvement in medical decisions and truth disclosure issues. NVivo software was used to identify common themes, and a thematic analysis method was utilised to analyse the datasets. Results This study identified three recurring themes relevant to the ethics and practice of truth disclosure: best interest rather than autonomy, the ambivalent value of deception and who understands what. The participants revealed that physicians often withhold fatal medical prognoses from terminally ill patients to ensure the best healthcare outcomes. The results indicate that deception towards patients is commonly accepted as a means of reducing burden and providing comfort. The participants opined that true medical information should be withheld from some patients, assuming that such disclosures may create a severe burden on them. Whether or to what extent medical information is disclosed primarily depends on a family’s wishes and preferences. Conclusions While truth disclosure to patients is considered an ethical norm in many cultures, such as in the U.K. and the U.S., the practice of concealing or partially revealing severe medical prognoses to patients is an actual medical practice in Bangladeshi society. This study emphasises the importance of recognising a patient’s active involvement and respecting the cultural values that shape family involvement in medical decision-making. These findings may have significant policy and practical implications for promoting patient autonomy within Bangladeshi family dynamics and religious-based cultural values. (shrink)