The integration of laser technologies with nanotheranostic platforms has opened new frontiers in the diagnosis and treatment of breast cancer. This review explores the pivotal role of lasers in enhancing both diagnostic precision and therapeutic efficacy within nanomedicine. On the diagnostic front, laser-based optical imaging techniques—such as photoacoustic imaging, fluorescence imaging using quantum dots or gold nanoclusters, and Raman spectroscopy—enable high-resolution, molecular-level detection of breast tumors. Laser-assisted biosensing, particularly surface-enhanced Raman spectroscopy and laser-activated microfluidic biosensors, further contributes to the rapid and sensitive identification of cancer biomarkers. In therapy, laser-driven approaches like photothermal therapy and photodynamic therapy offer noninvasive, targeted treatment options by harnessing nanoparticles that absorb laser light or activate photosensitizers to induce localized tumor cell destruction. Additionally, laser-triggered drug delivery systems—utilizing gold nanoshells and liposomes—enhance the precision and efficacy of chemotherapeutic interventions. Despite these advances, challenges remain, including the need for precise laser dosimetry, standardized nanoparticle-laser interactions, and long-term biocompatibility. Looking ahead, the convergence of laser technology with artificial intelligence, biodegradable nanoagents, and multimodal imaging-therapy platforms holds promise for personalized, safe, and highly effective breast cancer treatment. This review highlights the transformative potential of laser-enabled nanotheranostics in revolutionizing early detection, targeted therapy, and real-time monitoring of breast cancer.