Purpose: Evidence for optimizing the first-line chemotherapy for patients with metastatic triple-negative breast cancer (mTNBC) is lacking. This study assessed the utilization patterns of chemotherapy and associated survival outcomes in de novo mTNBC patients. Methods: Taiwan's cancer registry was utilized to extract study patients with newly-diagnosed breast cancer during 2011–2015 and confirmed metastatic triple-negative status.The patients’ medical records (e.g., diseases, treatments) and death status were obtained from the National Health Insurance Research Database. Utilization of first-line chemotherapy regimens was analyzed and associated survival outcomes were assessed using Cox models. Results: 93.60% of the mTNBC patients (n = 297) received chemotherapy, where combination regimens (75.54%) were more common than single-agent regimens (24.46%) in the first-line setting. A non-statistically lower all-cause death associated with combination versus single-agent chemotherapy (hazard ratio: 0.830 [0.589, 1.168]) was observed. Age was identified as a significant effect-modifier in treatment-associated survival outcomes (p = 0.008); younger patients (aged