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Triple-negative breast cancer (TNBC) is an aggressive subtype accounting for 10-17% of all breast cancers, characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. TNBC is associated with high recurrence rates and poor prognosis, particularly after metastatic progression. Current surveillance guidelines rely on clinical evaluation and conventional imaging, which have limited sensitivity for detecting early recurrence. [¹⁸F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) offers the potential to detect metabolic changes indicative of disease activity before anatomical changes become apparent. This review examines the emerging role of FDG PET/CT in the post-treatment evaluation of TNBC in two distinct clinical contexts: (1) surveillance for recurrence after remission, with specific attention to hepatic, pulmonary, osseous, and cerebral metastases, and (2) treatment response assessment in advanced disease following chemotherapy and immunotherapy. Across both contexts, FDG PET/CT offers incremental diagnostic and prognostic value over conventional imaging. However, much of the available evidence is derived from general breast cancer populations and not from TNBC-specific cohorts. Dedicated recurrence-surveillance data in TNBC remain particularly scarce. FDG PET/CT demonstrated 98% sensitivity and 100% specificity for hepatic metastases in a mixed-malignancy cohort, PET Response Criteria in Solid Tumors (PERCIST) criteria showed higher predictive accuracy than Response Evaluation Criteria in Solid Tumors (RECIST) for both progression-free and disease-specific survival, and early interim PET/CT after two cycles of chemotherapy identified metabolic non-responders (<42% SUV_max decrease) who had a 100% rate of residual tumor at surgery in a small TNBC cohort. However, FDG PET/CT remains limited for sub-centimeter pulmonary nodules (due to partial volume effects and respiratory motion) and brain metastases (due to high physiological brain glucose uptake). Additionally, limitations of the current evidence include small study populations, short follow-up periods, cost considerations, and risks of false-positive findings due to post-treatment inflammation and immunotherapy-related pseudoprogression. Beyond FDG, emerging PET tracers, such as radiolabeled fluorothymidine (FLT), fibroblast activation protein inhibitor (FAPI), and prostate-specific membrane antigen (PSMA)-targeted agents, may offer complementary information for TNBC surveillance. Larger, TNBC-specific prospective studies with longer follow-up are needed to establish evidence-based guidelines for incorporating FDG PET/CT into routine TNBC surveillance and response-assessment protocols, alongside formal cost-effectiveness analyses.