In the context of a traumatic event, such as a breast cancer diagnosis, talking with others about the event can facilitate emotional adjustment and meaning-finding. Among women with a history of breast cancer, open communication is likely to be of particular importance in the family setting, as the family is frequently a primary source of support. The goal of this cross-sectional survey study was to determine the association between open family communication about cancer and breast cancer survivors’ mental health. Responses from 230 women at various stages post-treatment suggest that the majority of women are able to talk openly with their family about breast cancer. Multivariate regression analysis further indicates that open family communication is independently associated with better mental health outcomes. Given that many women live long after a breast cancer diagnosis, maintaining mental health functioning is an important long-term goal. Efforts to enhance productive communication between patients and their family members may help women cope with and overcome the challenges of breast cancer survivorship.