Abstract: Breast cancer is one of the most common malignant tumors and the primary cause of cancer-related deaths in women globally. Approximately 70% of all breast cancers are hormone receptor-positive, and endocrine therapy is the main treatment for this cancer type. Endocrine therapy resistance often leads to treatment failure and the death of patients, which is a clinical problem that needs urgent solution. Research in the past few decades has shown that epithelial-mesenchymal transition (EMT) is a key event in cancer metastasis and associated with tumor treatment resistance. Increasing evidence suggests that EMT plays a key role in endocrine therapy resistance in breast cancer. This article reviews latest research on the relationship between EMT and endocrine resistance in breast cancer and discusses the specific molecular mechanisms involved, to provide new ideas and potential therapeutic targets for reversing endocrine therapy resistance in breast cancer.