AbstractStability and scalability are essential and urgent requirements for the commercialization of perovskite solar cells (PSCs), which are retarded by the non‐ideal interface leading to non‐radiative recombination and degradation. Extensive efforts are devoted to reducing the defects at the perovskite surface. However, the effects of the buried interface on the degradation and non‐radiative recombination need to be further investigated. Herein, an omnibearing strategy to modify buried and top surfaces of perovskite film to reduce interfacial defects, by incorporating aluminum oxide (Al2O3) as a dielectric layer and growth scaffolds (buried surface) and phenethylammonium bromide as a passivation layer (buried and top surfaces), is demonstrated. Consequently, the open‐circuit voltage is extensively boosted from 1.02 to 1.14 V with the incorporation of Al2O3filling the voids between grains, resulting in dense morphology of buried interface and reduced recombination centers. Finally, the impressive efficiencies of 23.1% (0.1 cm2) and 22.4% (1 cm2) are achieved with superior stability, which remain 96% (0.1 cm2) and 89% (1 cm2) of its initial performance after 1200 (0.1 cm2) and 2500 h (1 cm2) illumination, respectively. The dual modification provides a universal method to reduce interfacial defects, revealing a promising prospect in developing high‐performance PSCs and modules.