Emotional awareness (EA) is thought to facilitate psychological health by aiding emotion regulation in oneself and garnering social support from others. This study tested these potential relationships within a one-year longitudinal study of 460 women (age 23–91 years, mean 56.4 years) recently diagnosed with breast cancer (i.e., within four months). The women completed measures of emotional awareness, social support, social stress, affective symptoms, and well-being. Linear models tested EA as a moderator of social support and stress on affective symptoms and well-being. In those with higher EA, low social support was associated with greater depression and lower optimism. There was some evidence that higher EA predicted greater depression at baseline but lower depression at nine-month follow-up. These results support the idea that EA increases sensitivity to available social support and facilitates emotional adjustment over time, suggesting that assessment of EA could help guide clinicians in identifying those at greatest risk of adverse mental health outcomes in this population.