Breast cancer is one of the most common malignant tumors in women. Triple-negative breast cancer (TNBC) is a molecular subtype of breast cancer that is characterized by a high risk of recurrence and poor prognosis. With the increasingly prominent role of radiotherapy in TNBC treatment, patient resistance to radiotherapy is an attractive area of clinical research. Gene expression changes induced by multiple mechanisms can affect the radiosensitivity of TNBC cells to radiotherapy through a variety of ways, and the enhancement of radioresistance is an important factor in the malignant progression of TNBC. The above pathways mainly include DNA damage repair, programmed cell death, cancer stem cells (CSC), antioxidant function, tumor microenvironment, and epithelial-mesenchymal transition (EMT) pathway. Tumor cells can reduce the damage of radiotherapy to themselves through the above ways, resulting in radioresistance. Therefore, in this review, we aim to summarize the strategies for immunotherapy combined with radiotherapy, targeted therapy combined with radiotherapy, and epigenetic therapy combined with radiotherapy to identify the best treatment for TNBC and improve the cure and survival rates of patients with TNBC. This review will provide important guidance and inspiration for the clinical practice of radiotherapy for TNBC, which will help deepen our understanding of this field and promote its development.