Nanoemulsions (NEs), colloidal systems of nanoscale droplets (~100 nm), have emerged as transformative tools in oncology due to their high surface area-to-volume ratio, tunable physicochemical properties, and capacity for targeted drug delivery. While NEs find applications across diverse fields, their urgency in breast cancer therapy stems from critical limitations of conventional treatments, including systemic toxicity, poor bioavailability, and multidrug resistance. Unlike traditional chemotherapeutics, NEs enable precise tumor targeting via passive mechanisms (eg, enhanced permeability and retention effect) and active strategies (eg, ligand-functionalized surfaces), significantly reducing off-target effects. Their ability to encapsulate hydrophobic drugs, improve solubility, and sustain controlled release enhances therapeutic efficacy while overcoming resistance mechanisms prevalent in aggressive breast cancer subtypes, such as triple-negative and HER2-positive tumors. This review comprehensively analyzes NE formulation techniques (eg, ultrasonication, phase inversion temperature, bubble bursting), stability optimization through surfactant dynamics, and predictive modeling of droplet behavior. A focal point is their role in modulating tumor microenvironments, inducing apoptosis, and inhibiting angiogenesis in preclinical breast cancer models. By spotlighting NE-driven advancements in drug accumulation, reduced relapse rates, and adaptable combination therapies, this article underscores their potential to revolutionize oncology. Future research must prioritize clinical translation, scalability, and multifunctional NE designs to address unmet needs in precision breast cancer treatment.