The application of silicon is known to enhance crop tolerance against various environmental stresses. In terms of drought tolerance, however, studies only focusing on the effects of silicon on transpiration are available and thus relationships between silicon and physiological processes relating to crop drought tolerance remain unclear. Recent studies on water uptake and transport in crops revealed that silicon affected these traits and the effects differed among species. Other recent studies have shown relationships between silicon and dehydration tolerance at cell or tissue levels. In this review, we examine recent and past studies on the effects of silicon on crop drought tolerance to discuss whether the utilization of silicon could possibly enhance the drought tolerance of crops.