Adjuvant endocrine therapy improves overall survival for women with breast cancer. However, side effects may compromise patients' quality of life (QOL). This study examined how two communication variables (self-efficacy for symptom communication [SE] and holding back from discussing cancer-related concerns [HB]) relate to QOL, pain and menopausal symptoms. Participants with breast cancer (N = 61) completed questionnaires regarding symptoms, communication, and QOL. SE was positively related to QOL and negatively related to pain interference. HB from discussing cancer-related concerns was related negatively to QOL and positively to pain interference. HB mediated the relationship between SE and QOL as well as between SE and pain interference. Increased SE is beneficial among women on endocrine therapy for breast cancer. Future research should determine if interventions to improve SE are feasible and can improve QOL and symptom tolerability.