Breast cancer is the most common type of cancer and the most common cause of cancer-related mortality among women worldwide. However, the burden is not evenly distributed, and, according to the best available data, there are large variations in the incidence, mortality, and survival between different countries and regions and within specific regions. Many complex factors underlie these variations, including population structure (eg, age, race, and ethnicity), lifestyle, environment, socioeconomic status, risk factor prevalence, mammography use, disease stage at diagnosis, and access to high-quality care. We review recent breast cancer incidence and mortality statistics and explore why these vary so greatly across the world. Further research is needed to fully understand the reasons for variations in breast cancer outcomes. This will aid the development of tailored strategies to improve outcomes in general as well as the standard of care for underserved populations and reduce the burden of breast cancer worldwide.