In this study, we designed a surface phase-matched transmission enhancement top electrode–Ag/indium tin oxide (ITO) structure for highly efficient and aesthetic semitransparent organic photovoltaics (ST-OPVs). The purposed highly transparent back electrodes (Ag/ITO) could selectively decrease visible reflection and increase transparency accordingly. By altering the thicknesses of the Ag and ITO layers, we could control the transmittance curve and increase the transparency of the ST-OPV devices. Devices based on PTB7-Th:IEICO-4F and PM6:Y6:PC71BM displayed outstanding performance (8.1 and 10.2%, respectively) with high photopic-weighted visible light transmittance (36.2 and 28.6%, respectively). The outstanding visible and near-infrared light harvesting of PM6:Y6:PC71BM further allowed a new application: double-sided energy harvesting from solar and indoor illumination. The simple optical design of a top electrode displaying high transparency/conductivity has a wide range of potential applications in, for example, greenhouse photovoltaics, tandem cells, and portable devices.