Background: The prevalence of undertreated cancer pain remains high. Suboptimal pain control affects quality of life and results in psychological and emotional distress. Barriers to adequate pain control include fear of opioid dependence and its side effects. Aim: To investigate the attitudes and perceptions of morphine use in cancer pain in advanced cancer patients and their caregivers and to examine the influence of caregivers’ attitudes and perceptions on patients’ acceptance of morphine. Design: Qualitative study involving semi-structured individual interviews transcribed verbatim and analyzed thematically. Setting/Participants: A total of 18 adult opioid-naïve patients with advanced cancer and 13 caregivers ( n = 31) were recruited at a private tertiary hospital via convenience sampling. Results: Attitudes and perceptions of morphine were influenced by previous experiences. Prevalent themes were similar in both groups, including perceptions that morphine was a strong analgesic that reduced suffering, but associated with end-stage illness and dependence. Most participants were open to future morphine use for comfort and effective pain control. Trust in doctors’ recommendations was also an important factor. However, many preferred morphine as a last resort because of concerns about side effects and dependence, and the perception that morphine was only used at the terminal stage. Caregivers’ attitudes toward morphine did not affect patients’ acceptance of morphine use. Conclusion: Most participants were open to future morphine use despite negative perceptions as they prioritized optimal pain control and reduction of suffering. Focused education programs addressing morphine misperceptions might increase patient and caregiver acceptance of opioid analgesics and improve cancer pain control.