Breast cancer is the most common cancer in women and distant site metastasis is the main cause of death in breast cancer patients. Epithelial-mesenchymal transition (EMT) is defined by the loss of epithelial characteristics and the acquisition of a mesenchymal phenotype. EMT is a vital process for large-scale cell movement during morphogenesis at the time of embryonic development. Tumor cells usurp this developmental program to execute the multi-step process of tumorigenesis and metastasis. Understanding the biological intricacies of the EMT may provide important insights that lead to the development of therapeutic targets in pre-invasive and invasive breast cancer, and could be used as biomarkers for identifying tumor subsets with greater chances of recurrence, metastasis, and therapeutic resistance leading to death. The purpose of this article is to investigate the association between EMT and breast cancer.