Physical activity (PA) interventions have shown to be effective for improving health-related quality of life (HRQoL) in clinical populations, including people living with cancer. This chapter summarizes the current PA guidelines and the current evidence about exercise interventions aimed to improve HRQoL in people with breast cancer (BC). In people with BC undergoing systemic treatments and in BC survivors, exercise interventions including aerobic exercise, high-intensity interval training, resistance training, and aerobic exercise combined with resistance training improve HRQoL. Compelling evidence supports the need for undertaking PA as a health-related behavior and implementing exercise interventions in this population, particularly aerobic and resistance training. Mind-body practices and aquatic exercise might also improve HRQoL, although with smaller effects. Combining exercise with dietary interventions has also shown to have beneficial effects on all HRQoL domains in BC survivors. However, the benefits of PA on HRQoL in BC survivors are not maintained over time if PA is discontinued, which suggests that PA should become a daily habit in this population.