Gedunin is a secondary metabolite found in neem tree. Since the first discovery of this compound, its bio-active properties have been continuously evaluated. However, the low hydrophobicity of gedunin decreases its bioavailability and pharmacokinetic profile. In the present investigation, a new liposomal nanocarrier for co-delivery of gedunin and P-glycoprotein (P-gp) siRNA [siRNA coated liposomal gedunin (Lipo-Ged-siRNA)] was developed to improve the anti-proliferative activity of gedunin. Characteristics of prepared Lipo-Ged-siRNA demonstrated promising effects. Lipo-Ged-siRNA showed greater anti-proliferative effects (IC₅₀-8.5 µg/mL) followed by pure gedunin (IC₅₀– 40.2 µg/mL) in breast cancer stem cells (bCSCs). Immunofluorescence analysis demonstrated reduced expression of P-gp following exposure to Lipo-Ged-siRNA. Furthermore, Lipo-Ged-siRNA affected the expression of ABCB1, Cyclin D1, Bax, p53, and surviving genes in bCSCs.