Triple-negative breast cancer (TNBC) is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapeutic regimens. Resistance to current standard therapies such as anthracyclines or taxanes limits the available options for previously treated patients with metastatic TNBC to a small number of non-cross-resistant regimens, and there is currently no preferred standard chemotherapy. Duration of response is usually short, with rapid relapse very common and median survival of just 13 months. The newly approved agent eribulin has shown a survival benefit in patients who had previously been treated with anthracycline- or taxane-containing regimens, including in patients with TNBC. Platinum-based regimens are an emerging option for patients with BRCA1 mutation, and newer targeted agents such as anti-angiogenic treatment with bevacizumab or anti-epidermal growth factor receptor treatment with cetuximab, have shown some benefit in combination therapy. However, there remains an urgent unmet need for improved targeted agents for this patient population. Improved treatment may be facilitated by biomarker-led understanding of subgroup molecular targets, which may predict benefit from currently approved agents, as well as newer targeted drugs.