<p>Breast cancer remains one of the most prevalent causes of cancer-related mortality worldwide. Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that has a poor prognosis and limited therapeutic options. Smart nanocarriers have been developed through significant advancements in nanotechnology over the past few years. To increase therapeutic effectiveness while reducing systemic toxicity, recent developments in nanotechnology have led to the creation of smart nanocarriers—nanosystems designed to carry drugs in a targeted, stimulus-responsive manner. Liposomes, dendrimers, micelles, carbon nanotubes, and polymeric nanoparticles are among the most common types of smart nanocarriers discussed in this study. Their design principles and functional features characterize the many forms of smart nanocarriers. Targeting techniques specific to breast cancer are highlighted, with a particular focus on active targeting via ligands and tumor microenvironment-responsive systems applicable to TNBC. By examining the integration of biodegradable materials, green synthesis methods, and alignment with the global Sustainable Development Goals (SDGs), the study also underscores the crucial role of sustainability in nanomedicine. Significant advancements have been made, but several biological, regulatory, and therapeutic issues still hinder the practical application of nanomedicine in treating TNBC. This review highlights key translational roadblocks and proposes strategic solutions to bridge the gap between the bench and the bedside.</p> Graphical abstract <p></p>