Culex is the largest subgenus within the genus Culex that includes important vectors of diseases. The correct identification of mosquitoes is critical for effective control strategies. Wing geometric morphometrics (WGM) has been used to identify mosquito species alongside traditional identification methods. Here, WGM was used for eleven Culex species from São Paulo, Brazil, and one from Esquel, Argentina. Adult mosquitoes were collected using CDC (Centers for Disease Control) traps, morphologically identified and analyzed by WGM. The canonical variate analysis (CVA) was performed and a Neighbor-joining (NJ) tree was constructed to illustrate the patterns of species segregation. A cross-validated reclassification test was also carried out. From 110 comparisons in the cross-validated reclassification test, 87 yielded values higher than 70%, with 13 comparisons yielding 100% reclassification scores. Culexquinquefasciatus yielded the highest reclassification scores among the analyzed species, corroborating with the results obtained by the CVA, in which Cx. quinquefasciatus was the most distinct species. The high values obtained at the cross-validated reclassification test and in the NJ analysis as well as the segregation observed at the CVA made it possible to distinguish among Culex species with high degrees of confidence, suggesting that WGM is a reliable tool to identify Culex species of the subgenus Culex.