In this study, tropical oithonid copepod Dioithona oculata was recorded for the first time in the Mediterranean Sea. This species is distinguished easily by its large ocular lenses and by the number of setae on the endopod of the maxillule. The study was conducted seasonally in the coastal area of Iskenderun Bay between April 2013 and December 2016. D. oculata was first observed in October 2013 in the study area (Station 4; 3.1 Ind. m(-3)); after this period, this species became an important contributor to zooplankton assemblages in October with the highest level seen in 2016 (Station 4, 834.5 Ind. m(-3)). The proportion of this species in the copepod community varied from 0.14% (2014) to 29.4% (2016), and the highest proportions, observed in October 2016, were at Stations 3 and 4 (51.1% and 65.3%, respectively). Females dominated the D. oculata population and the ratio of female to male was 5.6 +/- 7 on average. Copcpodit stages were also observed in the population.