The aims of the study to examine population genetic structure and infer patterns associated with geography in populations of Orthotomicus tridentatus Eggers in Southern Turkey. The beetle only feeds on Cedrus libani which widely distributes along the Taurus Mountains. COI gene was used from 43 samples from eight populations along the entire Taurus Mountains. AMOVA results suggested that there is high gene flow among the populations. The results of the neutrality and mismatch tests show that widespread geographic distribution of O. tridentatus in Turkey is the result of the population range expansion model. According to NJ and ML, it is determined that the studied haplotypes did not compose any phylogenetic group depending on the geography. Also, low pairwise FST values put forward to that there is very high gene flow among the populations of the species. These results of the study suggests that the species could use the mountain systems as broad corridors for dispersal.