Sulfur plays an important role in determining the grain yield and quality of oilseed crops. However, little is known about the effect of sulfur foliar application on the yield, yield components, and oil content of sesame genotypes. Therefore, a two-year field factorial experiment with a basic complete randomized block design was conducted in Fasa city during 2017-2018. The effects of sulfur foliar application at five concentrations of S1, S2, S3, S4, and S5 as 0, 1, 2, 4, and 8 ml, respectively (0, 300, 600, 1200, and 2400 ml of liquid sulfur/ha) were examined on endemic and non-native sesame cultivars, namely C1: Darab 1, C2: local Fasa, C3: Iraqi, C4: Tak-Par Dashtestan, and C5: Shesh-Par Borazjan. Treatments with the concentrations of 6 and 8 ml of the sulfur foliar application without statistically significant differences with each other were superior to the other treatments in terms of such traits like the number of capsules per plant, thousand-grain weight (TGW), plant dry weight (PDW), grain yield (GY), harvest index (HI), and grain oil content. The highest number of seeds per capsule was obtained from a concentration of 8 ml sulfur foliar application. The results showed that all cultivars reacted to the increased sulfur levels. The highest GY and number of capsules per plant belonged to C1, C4, and C5, with C4 and C2 containing the highest contents of grain oil and protein, respectively. The interaction of C5 and a concentration of 8 ml sulfur spraying led to the highest yield, the number of capsules per plant, TGW, PDW, and HI. Positive and significant correlations were obtained among GY with the number of capsules per plant (r = 0.97**), HI (r = 0.91**), TGW (r = 0.85**), and grains per capsule (0.55*). It can, therefore, be concluded that the number of capsules per plant and TGW have greater effects on increasing the GY of sesame than the other yield components. The percentages of grain oil and protein had a high negative and significant relationship (r = −0.88**) and the percentage of grain protein decreased with increasing the percentage of oil. In this study, the treatments with concentrations of 6 and 8 ml of liquid sulfur and Shesh-Per Dashtestan cultivar were superior to the other treatments in terms of increasing GY per unit area.