Pain is one of the most common symptoms in cancer patients, and its management is a significant goal in supportive care. Many barriers interfere with its effective control. Nowadays, with a shift in care from the hospital to the home, there is an increasing tendency to involve family caregivers in pain management. Their beliefs may act as barriers to effective pain management in these homecare settings. This study aimed to validate and explore these beliefs using Barriers Questionnaire II (BQ II). A cross-sectional survey of 202 individuals from a cohort of family caregivers in Greece. The reliability index Cronbach, a value for the translated version of the BQ II, calculated >0.9. Most participants reported worries about the side effects of analgesics. They often assumed these effects were irreversible, and equally, there were concerns about addiction to these drugs. They agreed on the effectiveness of analgesics in treating cancer pain but disagreed that reporting pain is a distracting factor in active cancer treatment. This is the first time BQ II has been used in this population. The results are consistent with the international academic studies in this area, but more research is needed. BQ II was found to be a valid and reliable scale for defining caregiver attitudes and barriers to effective pain management in homecare settings. Health professional training, interventions targeted to caregivers and trained home care teams may improve the quality of cancer care in these settings.