Motivating women with breast cancer to engage in regular physical activity may be an enormous challenge given the common side effects of breast cancer treatment. The objective of this narrative review is to briefly summarize recent research evidence examining the influence of physical activity on commonly occurring side effects of breast cancer treatment. Overall, current research evidence indicates that regular participation in physical activity after breast cancer diagnosis may mitigate common side effects of breast cancer adjuvant therapy, including fatigue, depression, impaired quality of life, decreased muscular strength, decreased aerobic capacity, and weight gain. Future research could examine the influence that physical activity has on the effectiveness of breast cancer treatment. Implications for health care professionals are discussed.