This research was conducted to determine the adaptability of some sesame (Sesamum indicum L.) varieties as a second crop under semi-arid climatic conditions during 2014 and 2015. The experiment was conducted on the research area of Agricultural Faculty, Kezer Campus, Siirt University, Turkey. Thirteen registered sesame species were used as material in the experiment. The experiment was carried out in a randomized block design with four replications. Planting of sesame seeds was performed by hand following the harvest of wheat planted as the first crop. The plant height, number of side branches in the plant, the first branch height in the plant, the number of capsules per plant, the number of seeds per capsule, the weight of 1000 seeds, seed yield, fat content, fat yield and protein content were determined in the study. The results of two-year study revealed that 10 out of 13 varieties were not suitable to semi-arid climatic conditions (Siirt province ecological conditions). The varieties which were not adopted to semi-arid climatic conditions (Tan 99, Sarisu, Tanas, Ozberk 82, Kepsut 99, Muganli 57, Baydar 2001, Ottoman 99, Orhangazi 99 and Cum-huriyet 99) are widely cultivated sesame cultivars in the Aegean and Mediterranean regions. The other three varieties (Arslanbey, Hatipoglu and Boydak) are mostly recommended for the Southeastern Anatolia Region. The study clearly revealed the importance of genotype x climate interaction in adaptation of sesame species to a region.