ackground: Natural compounds such as fisetin have promising in breast cancer treatment, but their poor pharmacokinetics limit their therapeutic application. This study utilized a synergistic approach by combining fisetin-loaded Nigella sativa (N.S.) oil nanovesicles (FIS-NSs) and carbohydrate-based microneedles (FIS-NSs-MNs) to improve breast cancer management. Methods: Chemical composition of NS petroleum ether extract using gas chromatography–mass spectrometry (GC/MS). FIS-NSs were prepared and characterized for particle size, polydispersity, zeta potential, encapsulation efficiency, and stability. These vesicles were embedded into gelatin, hyaluronic acid, and carboxymethyl cellulose mi- croneedles. In vitro drug release, ex vivo permeation, cytotoxicity against breast cancer cells, and in vivo antitumor efficacy in Ehrlich tumor models were evaluated. Results: Optimized FIS-NSs displayed nanoscale size (190 ± 0.74 nm), low P.D.I (0.25 ± 0.07), high surface charge (+37 ± 0.57 mV), and high encapsulation (88 ± 0.77%). In vitro in- vestigations showed sustained FIS release (~85% over 72 h), while ex vivo permeation showed higher absorption than free fisetin. Both FIS-NSs and FIS-NSs-MNs showed dose-dependent cytotoxicity against breast cancer cells, with lower IC50 than free fisetin (24.7 μM). In vivo , FIS-NSs-MNs and tumor burden inhibition (~77%), reduced oxidative stress (54%), restored antioxidant defenses, and decreased inflammatory markers. Immuno- histochemical analysis for caspase-3 showed apoptosis activation within tumor tissues. Conclusions: These findings demonstrate that FIS administration via NS-MNs improves drug stability, penetration, and apoptotic activity, resulting in enhanced anticancer effects. This innovative nanovesicle–microneedle platform provides a non-invasive, effective, and