The direct and indirect (grand maternal and maternal) photoperiod influence on the diapause percentage of Wolbachia-infected and uninfected Trichogramma brassicae Bezdenko (Hym: Trichogrammatidae) were investigated under laboratory conditions. In order to study the grand maternal effect of photoperiod on diapause induction, grand maternal and maternal generation developed at 20°C and day length of 0, 3, 6, 9, 12, 15, 18, 21 and 24 h and 20°C and day length of 10 h, respectively and progeny generation developed at 10°C and 14°C and absolute darkness. To study the effect of maternal photoperiod on diapause induction, maternal generation developed at 20°C and day length of 0, 3, 6, 9, 12, 15, 18, 21 and 24 h and progeny generation developed at 10°C and 14°C and absolute darkness. To determine the direct effect of photoperiod on diapause induction, maternal generation developed at 20°C and day length of 10 h and progeny generation developed at 10°C and 14°C and day length of 0, 3, 6, 9, 12, 15, 18, 21 and 24 h. The results revealed significant influence of Wolbachia infection, photoperiod, temperature, and their interactions on the percentage of diapausing individuals in all cases (grand maternal, maternal and direct effect of photoperiod). Experiments showed that under the short days (9 and 12 h) and permanent light, the percentage of diapausing individuals was significantly higher than under the ultra-short, long and ultra-long days. A somewhat similar pattern of photoperiodic reaction (indirect and direct photoperiod reaction) was observed in both infected and uninfected T. brassicae however the results showed that uninfected population was more successful in diapause entering than infected one which might be the result of Wolbachia infection. The results indicated that exposure to diapause induction conditions for more than one generation increased the percentage of diapausing individuals.