A promising strategy as a cancer therapeutic is tumor-targeted gene delivery. The AG73 peptide derived from the laminin alpha1 chain is a ligand for syndecans, and syndecan-2 is highly expressed in some cancer cells. In this study, AG73-PEG liposomes were developed for selective gene delivery to syndecan-2 overexpressing cancer cells. AG73-PEG liposomes were used in combination with Bubble liposomes and ultrasound exposure to enhance transfection efficiency by promoting the escape of the liposomes from the endosome to the cytosol. AG73-PEG liposomes showed selective gene delivery to syndecan-2 overexpressing cancer cells. Furthermore, AG73-mediated liposomal gene transfection efficiency was enhanced by 60-fold when Bubble liposomes and ultrasound exposure were used, despite the absence of an increase in the uptake of AG73-PEG liposomes into the cells. Confocal microscope analysis revealed that the Bubble liposomes and ultrasound promoted intracellular trafficking of the AG73-PEG liposomes during gene transfection. Thus, the combination of AG73-PEG liposomes with Bubble liposomes and ultrasound exposure may be a promising method to achieve selective and efficient gene delivery for cancer therapy.