Breast cancer (BC) ranks among the most diagnosed solid tumors worldwide. For decades, significant research efforts have been dedicated to finding selective treatments for these solid tumors. Currently, the primary treatment method for BC involves surgery, with the subsequent utilization of radiotherapy and chemotherapy. However, these subsequent treatments often fall short of effectively treating BC due to their side effects and harm to healthy tissues. Today, a range of nanoparticles are being developed to target BC cells without affecting the surrounding healthy tissues. This in-depth review, based on studies, seeks to shed light on these specially designed nanoparticles and their potential in BC treatment. Typically, therapeutic drugs or naturally occurring bioactive compounds are incorporated into precisely crafted nanoparticles. This enhances their solubility, longevity in the bloodstream, and distribution in the body while also minimizing side effects and immune reactions. Nanoparticles have been designed to address the shortcomings of standalone therapeutics and traverse various biological obstacles spanning the systemic, microenvironmental, and cellular that differ among patients and diseases. We prioritize breakthroughs in nanoparticle design to surpass diverse delivery obstacles and believe that smart nanoparticle engineering not only enhances effectiveness for general delivery but also allows customized solutions for specific needs, ultimately leading to better outcomes for patients.