To study the effect of salinity on seed yield and yield components, morphological characteristics and leaf chlorophyll content of sesame, a factorial experiment based on completely randomized design with three replications was conducted at research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad. Treatments comprised five salinity levels (2.4, 4.4, 6.4, 8.4 and 10.4 dSm^-1) and four sesame genotypes, including Giroft, Dezful, Moghan and Borazjan. Results showed that salinity had a significant effect on morphological characteristics and leaf chlorophyll content. The morphological characteristics also showed significant differences between sesame genotypes. The effect of salinity stress on plant height, total dry weight, root dry weight, root dry weight to shoot dry weight ratio and yield components was significant and decreased with increasing salinity levels. The lowest seed yield per plant was observed at salinity level of 10.4 dSm^-1.­­Chlorophyll content was increased with increasing salinity levels up to 6.4 dSm^-1 and decreased at the highest salinity level. Nevertheless, the leaf chlorophyll content and its corresponding chlorophyll meter number were reduced by increasing plant age. Results showed that at high salt concentrations, root/shoot dry weight ratio of Moghan was higher than other genotypes. The rate of increase in chlorophyll meter number of Moghan was much higher than in other genotypes at high salinity levels and this genotype showed the lowest variation in seed weight per plant and yield components by increasing salinity. So, It seems that amongst studied genotypes, Moghan can be evaluated as a resistant one in the field experiments.