Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic form of breast cancer characterized by the absence of hormonal receptors with a poor prognosis and limited treatment options. Addressing this challenge has become an urgent priority, driving substantial scientific efforts in this area. In recent years, inorganic nanoparticles have emerged as promising agents for the therapeutic and diagnostic management of this malignancy. Their unique physicochemical properties such as exceptional stability, uniform size, ease of surface functionalization, and distinctive optical and magnetic characteristics have positioned them as highly attractive candidates for these applications. This review primarily focuses on the therapeutic and diagnostic applications of inorganic nanoparticles, summarizing key research findings that demonstrate their efficacy against TNBC. Additionally, it addresses the toxicological concerns associated with these nanoparticles and explores advanced strategies to mitigate their adverse effects, thereby improving their clinical utility. Finally, the review concludes with a concise discussion of the prospects of these nanoparticles in biomedicine.