A surface acoustic wave (SAW)-driven light shutter is demonstrated using polymer- dispersed liquid crystals (PDLCs). Our experiments show that a PDLC film switches from a non-transparent state to a transparent state when subjected to a SAW. The working mechanism is analyzed theoretically and the acousto-optic properties of the PDLC film are characterized. This switching behavior results from the acoustic streaming-induced realignment of liquid crystal (LC) molecules as well as SAW-induced thermal diffusion. Such a device shows an excellent performance in terms of imaging quality and optical contrast, which is important for display applications and smart windows.