Abstarct: Lack of water is one of the most important limiting factors of crop growth in arid and semiarid areas. This factor, in addition to reduce growth and yield crop, causes the disorder of nutrient absorption. Therefore the application of nano-fertilizers in different environmental conditions is considered in crop production. So, in order to evaluate the effects of different concentrations of iron oxide nanoparticles on yield and quality characteristics of sesame (Sesamum Indicum L.) under drought stress, a split plot experiment baxsed on randomized complete block design with three replications was conducted agricultural collage, university of shahrood. The experiment factors was included three levels of irrigation including a1= control (irrigation 8 days), a2 = irrigation 12 days and a3 = irrigation 16 days as main plot and four levels foliar application of iron oxide nanoparticles including b1 = control (without any fertilizer), b2 = 0.5 kg per thousand liters as sub factor, b3= 1 kg per thousand liters of water and b4 = 1/5 kg per thousand liters of water as subplots. The results showed the interaction between drought stress and iron oxide nanoparticles had significant effect on grain yield, biomass production, stomata conductance, chlorophyll b, the amounts of carotenoid in the leaves, grain protein, proline, catalase activity and seed iron content. The highest grain yield, biomass production and seed iron content were obtained at a1b3 treatment, the highest stomata conductance was in a1b2 and proline concentration was in a3b2 treatment. The main effect of drought stress was significant on some characteristics such as the number of seeds per capsule, 1000-seeds weight and chlorophyll "a". In this study, the main effects of iron oxide nanoparticles was significant on guaiacol peroxidase activity and seed oil percent, while the drought stress and iron oxide nanoparticles, alone, had a negative effect on potassium of sesame seeds. Generally the results can be concluded, that iron oxide nanoparticles about 0.5 to 1 kg per thousand liters of water, could be able to prevent the adverse effect of drought stress on grain yield and quality characteristics of sesame by improving the physiological processes of Sesame plant under drought stress.