Body size is one of the most significant features of organisms and is correlated with a large number of ecological and physiological variables. Similar to size, biological shape is one of the most conspicuous aspects of an organism's phenotype and provides a link between the genotype and the environment. Body size may change with altitude and also habitat differences associated with altitude may affect the biological shape and some morphological characteristics. Four populations of Aedes vexans Meigen occurring in different ecological subregions at altitudes between 808-1,620 m in the Aras Valley from northeastern Turkey were compared using traditional and geometric morphometrics. When the wing shape differences of populations were analyzed by UPGM, the cluster analyses recognized two main groups of populations. Godekli (808 m) comprised the first group while Zulfikar (848 m), Surmeli (944 m), and Cilehane (1,620 m) populations comprised the second group. In the second group, Zulfikar and Cilehane populations showed a similar grouping pattern while Surmeli appeared as a different group. Centroid sizes were used as measures of overall wing size differences among different regions. Aedes vexans from the Surmeli region had relatively larger wings. Journal of Vector Ecology 36 (1): 30-41. 2011.