Abstract: Triple-negative breast cancer (TNBC) is characterized by high histological grade, advanced clinical stage, invasiveness, and high incidence of metastasis. Because of the lack of effective therapeutic targets, traditional chemotherapy remains the mainstay for treating patients with TNBC. As a highly heterogeneous disease, TNBC requires more accurate predictive biomarkers. The development of omics techniques and initiation of clinical trials have become avenues for exploration of new prognostic biomarkers of adjuvant chemotherapy, encompassing different elements such as genes, proteins, and components of the microenvironment, as well as the multi-molecule combined analysis. Thus, in this review, we summarize prognostic biomarkers for TNBC in patients undergoing adjuvant chemotherapy, potential molecular mechanisms, and directions for future development.