<p>The thioredoxin system, comprising thioredoxin (Trx) and thioredoxin reductase (TrxR), is a central regulator of cellular redox homeostasis and plays essential roles in normal brain physiology and redox signaling. In glioblastoma (GBM), this system undergoes profound pathological rewiring, creating a redox dependency that represents a potential therapeutic vulnerability. The overexpression of Trx and TrxR in GBM promotes tumor proliferation, invasion, angiogenesis, and resistance to chemotherapy and radiotherapy, while the endogenous Trx inhibitor, thioredoxin-interacting protein (TXNIP), is frequently downregulated. This imbalance drives redox adaptation and sustains tumor survival under metabolic and therapeutic stress. Pharmacological modulation of the Trx system using synthetic inhibitors, such as auranofin, platinum-based compounds, and PX-12, as well as selected natural compounds including curcumin analogs and flavonoids, has shown efficacy in preclinical GBM models by inducing oxidative stress and enhancing sensitivity to standard therapies. Emerging evidence also suggests that Trx system targeting may modulate the tumor immune microenvironment, providing a rationale for combination strategies with immunomodulatory approaches. Overall, targeting the Trx system represents a promising precision oncology strategy for GBM. Future efforts should focus on the development of brain-penetrant inhibitors, rational combination therapies, and predictive biomarkers to facilitate clinical translation. Given the essential role of the Trx system in normal brain homeostasis, therapeutic targeting requires careful consideration of safety, therapeutic index, and tumor-selective vulnerabilities. This narrative review discusses current evidence on the physiological functions of the Trx system in the brain, its dysregulation in GBM, and its relevance as a precision therapeutic target.</p> Graphical Abstract <p></p>