Plants have developed highly complex response mechanism to drought stress, which can have lethal effects under severe conditions. In order to increase the drought tolerance of plants different technologies have been used. Nanotechnology, the novel approach to increase drought tolerance, is simply defined as using tools and materials at nano size, which is employed in agriculture in different areas like nanofertilizers, nanopesticides, nanosensors and nanoparticles. The effect of nanoparticles starts with increasing the water uptake ability of seeds, which raises seed germination and development under drought stress and continuous with increasing seed vigor index. Besides, application of nanoparticles increases the photosynthesis rate, chlorophyll content, photosynthetic enzyme activities, nitrogen metabolism and leaf activities like MDA, proline index of plants. Moreover, nanoparticles have the ability of penetrating cell nucleus and changing the gene expression levels related with drought stress response. Recent studies present the possible usage of nanotechnology to increase the drought stress tolerance of plants and the results show that the nanotechnology is an alternative tool against drought stress.