Objective: In women with breast cancer, many disease-related psychosocial factors directly affect quality of life (QoL) during and after treatment. The aims of this prospective study were to evaluate the psychosocial factors affecting QoL and its dimensions, to study their evolution over time, and to determine the factors associated with this evolution. Methods Thirty women with non-metastatic breast cancer were asked to complete a number of questionnaires evaluating QoL and its dimensions, symptoms of anxiety and depression, body image, social support, and coping strategies immediately after their diagnosis of breast cancer (T1), at the end of treatment (T2), and 6 months after the end of treatment (T3). Results: Level of education, mastectomy, and hormonotherapy all had an impact on QoL. QoL and its dimensions changed over time. Coping strategies, social support, body image, and symptoms of anxiety and depression were predictive factors for QoL. Conclusion: The identification of these predictive factors should help medical teams to identify the patients who are most vulnerable and susceptible to poor QoL. In women with breast cancer, it is essential to identify and treat any changes in patients' need for support in an appropriate manner, both during the course of therapy and particularly during remission.