Families are a unique source of support for many cancer patients. Most advanced communication skills training for oncologists are patient centred and do not cover interactions with family members. The current study used in-depth qualitative interviews of patients, relatives and cancer clinicians with thematic analysis to explore the role of family members in the communication process. Forty-one participants included 10 cancer patients, 10 relatives ensuring proportionate representation of both gender and primary cancer site and 21 doctors representing both medical and surgical oncology. Nineteen of 20 patients and relatives wanted an “open and honest” discussion with their doctors. All patients, relatives and doctors preferred involvement of the family at most stages of cancer treatment. Five themes were identified in relation to communication with family members. The participants highlighted the “importance of family for physical and psychological care,” they emphasised the need to “balance patient autonomy and relatives desire to be protective” using varied “negotiating strategies” that are influenced by “socioeconomic circumstances of both patient and family.” The doctor-patient-relative communication process was not static with preferences changing over time. The data suggests that communication skills training of cancer clinicians should incorporate modules on better communication with relatives.