Ethnic differences in breast cancer survival have been a long-standing concern. The objective of this article is to present relevant studies for all major US racial/ethnic groups including African-Americans, Latinos, Native Americans, Japanese-Americans and Native Hawaiians, and to discuss underlying causes of disparity. In comparison to Caucasian women, African-American women continue to experience the poorest breast cancer-specific survival of all ethnic groups in the USA. The prognosis for Latinos, Native Hawaiians and Native Americans is intermediate, better than for African-Americans but not as good as for Caucasians, whereas Japanese-American women tend to have better outcomes. The following possible contributors to the observed differences are discussed in detail: unfavorable distribution of stage at diagnosis due to low screening rates, limited access to care and treatment, tumor type, comorbidities, socioeconomic status, obesity and physical activity.