This qualitative study examined the questions of what cancer support groups provide that other supportive relationships do not, and what the self perceived consequences are of support group attendance. Nine representative Australian cancer peer support groups, consisting of a total of 93 interviewees, 75 women, and 18 men, with a mean age of 62, took part in participant observation and focus group interviews, with the data analysed using positioning theory. Support groups were positioned by participants as providing a unique sense of community, unconditional acceptance, and information about cancer and its treatment, in contrast to the isolation, rejection, and lack of knowledge about cancer frequently experienced outside the group. Groups were also positioned as occasionally emotionally challenging, in contrast to the experience of normalising support from family and friends. Increased empowerment and agency were positioned as the most significant consequences of group support, consisting of increased confidence and a sense of control in relation to self, living with cancer, and interactions with others, in particular the medical profession. The support group was also positioned as facilitating positive relationships with family and friends because of relieving their burden of care, by providing a safe space for the expression of emotion. No difference was found between professionally led and peer led support groups, suggesting that it is not the professional background of the leader which is of importance, but whether the group provides a supportive environment, mutuality, and a sense of belonging, and whether it meets the perceived needs of those attending. It is suggested that future research should examine the construction and experience of social support in those who drop out of, or who do not attend, cancer support groups, in order to provide further insight into the contrast between social support within groups and support in other contexts.