Photoperiod is one of the most important factors driving sexual maturation in fish. This study showed the effect of artificial photoperiod program on the maturation stages of Gilthead Sea bream in captivity. A total number of 78 Gilthead Sea bream (Sparus aurata) broodstock (48 male and 30 female) of 295.56 g and 332.03 g average body weight, respectively, fishes were collected and kept in indoor fiber circular tanks filled with salt water and under controlled photoperiods. They were divided into 2 groups. The first group was exposed to water temperature 22 ± 1 ̊ C, natural photoperiod and natural light intensity (control). Fish of the second group was kept at water temperature 22 ± 1° C and exposed to artificial photoperiod program with 600 lux light intensity. The experiment was conducted for 4 months. At the end of every month Gonadosomatic Index (GSI %) and histological sections were done.  Results showed that GSI value was highest in second group after the third month in female and in second month in male when compared to fish in the control group.  The histological sections confirmed these results. It could be concluded that photoperiod program is an initiative for reproductive cycle and gonadal maturation but it couldn't reach the final maturity and can induce spawning of gilthead sea bream in captivity.